Control valve assembly for a fluid heating system

ABSTRACT

A control valve assembly may include a housing, an inlet, an outlet, and a plurality of thermostatic control valves biased toward a closed position and arranged within the housing between the inlet and the outlet. The thermostatic control valves may each be associated with separate respective flow paths between the inlet and the outlet and have different operating temperatures. The valves may be configured to open at their respective operating temperatures and remain open unless the fluid falls below their respective operating temperature such that when multiple thermostatic control valves are open the amount of fluid flowing through the control valve is equal to the addition of the amount of fluid flowing through each valve. The operating temperatures and the flow rates of the thermostatic control valves may be selected to limit the passage of pathogens through the control valve assembly. A degassing valve may also be provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. Provisional PatentApplication No. 62/085,699 filed on Dec. 1, 2014, entitled MathematicalModel for the Inactivation of Biological Contaminates Using SolarHeating and U.S. Provisional Patent Application No. 62/259,748 filed onNov. 25, 2015, entitled Fluid Heating System, the contents of which arehereby incorporated by reference herein in their entireties. Inaddition, the present application is related to U.S. Non-Provisionalpatent application Ser. No. 14/954,091 filed on Nov. 30, 2015, entitledDual Axis Tracking Device, U.S. Non-Provisional patent application Ser.No. ______ filed on Nov. 30, 2015, entitled Fluid Heating System, andU.S. Non-Provisional application Ser. No. ______ filed on Nov. 30, 2015entitled Method of Calculating Pathogen Inactivation for a Fluid HeatingSystem, the contents of each of which are hereby incorporated byreference herein in their entireties.

FIELD OF THE INVENTION

The present application relates to a fluid heating system and associatedmechanisms and devices. More particularly, the present applicationrelates to a solar fluid heating system for use in heating, thermallypasteurizing, or otherwise treating water or other fluid. Still moreparticularly, the present application relates to a passive orsubstantially passive solar tracking and fluid heating system forheating, thermally pasteurizing, or otherwise treating water or otherfluid. Several of the associated mechanisms and devices haveapplicability outside the context of fluid heating or solar fluidheating. Accordingly, while several systems and devices are described inthe context of solar collection and fluid heating, it is to beunderstood that applicability in other situations and for other purposesapplies.

BACKGROUND

Thermal pasteurization may refer to raising water or other fluidtemperature to make the water or fluid safe. In the case water, thewater may be safe to drink, for example, after it is pasteurized. Thepasteurization may not result in all pathogens being killed orinactivated, but may reduce the pathogen level to a level suitableand/or safe for human consumption. Accordingly, pasteurization may notbe the same as sterilization. Moreover, pasteurization may not removeparticulates or turbidity from water. However, in comparison to otherpasteurization processes such as slow/rapid sand filters, chemicaltreatments, and use of ultraviolet light, thermal pasteurization is notnegatively impacted by turbidity. This feature makes thermalpasteurization particularly advantageous for water or fluid that may beless than clear.

Thermal pasteurization has been thought of as a batch or flow-throughprocess. In a batch process, water or fluid containers may be heated byburning fuels or by exposure to sunlight. For a flow-through process,the water or fluid may be heated while it passes through a pipe or ductand emerges as pasteurized. Batch processes may be less expensive tomanufacture, but they may be more expensive to operate due to the needto bring the system up to a suitable temperature each time a new batchis started.

Inactivation and rates of inactivation of various pathogens vary basedon the type of pathogen and, while it is common to bring water to a boilto assure inactivation of pathogens, most pathogens may be inactivatedat temperatures below boiling. However, it remains that inactivationrates increase rapidly as temperatures increase.

BRIEF SUMMARY OF THE INVENTION

The following presents a simplified summary of one or more embodimentsof the present disclosure in order to provide a basic understanding ofsuch embodiments. This summary is not an extensive overview of allcontemplated embodiments, and is intended to neither identify key orcritical elements of all embodiments, nor delineate the scope of any orall embodiments.

In one or more embodiments, a control valve assembly for passivelycontrolling flow of fluid may include a housing, an inlet, an outlet,and a plurality of thermostatic control valves biased toward a closedposition and arranged within the housing between the inlet and theoutlet. The thermostatic control valves may each be associated withseparate respective flow paths between the inlet and the outlet and havedifferent operating temperatures. The valves may be configured to openat their respective operating temperatures and remain open unless thefluid falls below their respective operating temperature such that whenmultiple thermostatic control valves are open the amount of fluidflowing through the control valve is equal to the addition of the amountof fluid flowing through each valve. The plurality of thermostaticcontrol valves may include three valves. The operating temperatures ofthe thermostatic control valves may be selected to limit the passage ofpathogens through the control valve assembly. The flow rates of thethermostatic control valves may be selected to limit passage ofpathogens through the control valve assembly. The operating temperaturesand the flow rates of the thermostatic control valves may be selected tolimit the passage of pathogens through the control valve assembly.

In one or more embodiments, a first valve of the plurality ofthermostatic control valves may have a range of flow rates and a valveclosing time associated with the amount of time it takes the valve toclose and a portion of a first flow path associated with the first valveextends from the chamber to the first valve and has a length selectedsuch that fluid flowing from the chamber through the portion of thefirst flow path to the valve at the range of flow rates will not reachthe valve in a time less than the closing time.

In one or more embodiments, a degassing valve may include a cap securedto a housing over a chamber. The cap may include a gas relief orifice.The valve may also include a float arranged in the chamber andconfigured to articulate between an open position and a closed positionwithin the chamber. The float may provide a closing force based on itsbuoyancy when arranged in the closed position. A linkage may be operablyconnected to the cap and the float. The linkage may have a sealingstopper configured to seal the gas relief orifice when the float is in aclosed position. The linkage may further be configured to magnify theclosing force of the float such that a sealing force provided on thesealing stopper by the linkage is a multiple of the float force. Themultiple of the float force may range from approximately 10 toapproximately 30 or from approximately 15 to approximately 25, or fromapproximately 16 to approximately 20. The linkage may include a bottomlinkage bar, a strut, and a top linkage bar. The float may engage thebottom linkage bar at a first end and the bottom linkage bar may bepivotable at a second end about a pivot point having a fixed positionrelative to the cap and the strut may engage the bottom linkage betweenthe first end and the second end. The strut may engage the bottomlinkage bar at a midpoint closer to the second end than the first end.The strut may engage the top linkage bar at a first end and the toplinkage bar may be pivotable at a second end about a pivot point havinga fixed position relative to the cap and the sealing stopper may bepositioned on the top linkage bar between the first end and the secondend. The sealing stopper may be arranged on the top linkage bar at amidpoint closer to the second end than the first end.

While multiple embodiments are disclosed, still other embodiments of thepresent disclosure will become apparent to those skilled in the art fromthe following detailed description, which shows and describesillustrative embodiments of the invention. As will be realized, thevarious embodiments of the present disclosure are capable ofmodifications in various obvious aspects, all without departing from thespirit and scope of the present disclosure. Accordingly, the drawingsand detailed description are to be regarded as illustrative in natureand not restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims particularly pointing outand distinctly claiming the subject matter that is regarded as formingthe various embodiments of the present disclosure, it is believed thatthe invention will be better understood from the following descriptiontaken in conjunction with the accompanying Figures, in which:

FIG. 1 is a perspective view of a fluid heating system, according to oneor more embodiments.

FIG. 2 is a perspective view of a solar collection system portion of thefluid heating system, according to one or more embodiments.

FIG. 3 is a side and back view thereof, according to one or moreembodiments.

FIG. 4 is a perspective view of a frame portion of the solar collectionsystem, according to one or more embodiments.

FIG. 5 is a perspective view of a rib of the frame portion, according toone or more embodiments.

FIG. 6 is a perspective view of a connection of a rib and a longitudinalrail, according to one or more embodiments.

FIG. 7 is a perspective view of a reflective element of the solarcollection system, according to one or more embodiments.

FIG. 8 is a perspective view of a fluid portion support element of thesolar collection system, according to one or more embodiments.

FIG. 9 is a perspective view of a fluid control system of the fluidheating system, according to one or more embodiments.

FIG. 10 is a close-up perspective view of portions of the fluid controlsystem, according to one or more embodiments.

FIG. 11 is a perspective view of a fluid heating element of the fluidcontrol system, according to one or more embodiments.

FIG. 12 is a close-up perspective view of the fluid heating element,according to one or more embodiments.

FIG. 13A is a perspective view of an engagement detail of the elongatedflow element and the return line, according to one or more embodiments.

FIG. 13B is a cross-sectional view thereof, according to one or moreembodiments.

FIG. 14 is a schematic diagram of a flow control assembly, according toone or more embodiments.

FIG. 15 is an exploded view of a flow control assembly, according to oneor more embodiments.

FIG. 16 is a cross-sectional view thereof, according to one or moreembodiments.

FIG. 17 is a free-body diagram of a linkage of a degassing valve,according to one or more embodiments.

FIG. 18A is a perspective view of a degassing valve, according to one ormore embodiments.

FIG. 18B is an exploded view thereof, according to one or moreembodiments.

FIG. 18C is a cross-sectional view thereof, according to one or moreembodiments.

FIG. 19A is a perspective view of a heat exchanger, according to one ormore embodiments.

FIG. 19B is an exploded view thereof, according to one or moreembodiments.

FIG. 20 is a perspective view of a tracking device and payload,according to one or more embodiments.

FIG. 21 is a perspective view of the tracking device of FIG. 20,according to one or more embodiments.

FIG. 22A is a detail view of a first actuation assembly, according toone or more embodiments.

FIG. 22B is a detail view of a second actuation assembly, according toone or more embodiments.

FIG. 23 is a flow diagram depicting a method of tracking a moving objectand directing a payload toward the object, according to one or moreembodiments.

FIG. 24A is a graphical representation of an azimuth and altitude of anobject in relation to a tracking device, according to one or moreembodiments.

FIG. 24B is a graphical representation of first and second motion pathsof a tracking device, based on the azimuth and altitude of FIG. 24A,according to one or more embodiments.

FIG. 25 is a graphical representation of the calculation of the firstmotion path and the second motion path, according to one or moreembodiments.

FIG. 26A is a graphical representation of the calculation of the firstlinear motion, according to one or more embodiments.

FIG. 26B is an illustration of the location of the variables used tocalculate the first linear motion with respect to the first actuationassembly, according to one or more embodiments.

FIG. 27A is a graphical representation of the calculation of the secondlinear motion, according to one or more embodiments.

FIG. 27B is an illustration of the location of the variables used tocalculate the second linear motion with respect to the second actuationassembly, according to one or more embodiments.

FIG. 28 is a block diagram depicting aspects of a control module,according to one or more embodiments.

FIG. 29 is a flow diagram depicting a method of populating an errorcorrection lookup table, according to some embodiments.

FIG. 30 is a flow diagram depicting a method of tracking a moving objectand directing a payload toward the object, according to someembodiments.

FIG. 31 is a graphical representation of the temperature of fluid in thefluid heating system at particular locations over time, according to oneor more embodiments.

FIG. 32 is a schematic diagram of the temperature locations of FIG. 20,according to one or more embodiments.

FIG. 33 is a table showing parameter data for calculating thetemperature of the fluid in the fluid heating system, according to oneor more embodiments.

FIG. 34 is a graphical representation showing correspondence betweencalculated temperatures and experimental temperatures.

FIG. 35 is a graphical representation of the temperature of fluid in thefluid heating system at particular locations over time, according to oneor more embodiments.

FIG. 36 is a graphical representation of the temperature of fluid in thefluid heating system at particular locations over time, according to oneor more embodiments.

FIG. 37 is a graphical representation of the temperature of fluid in thefluid heating system at particular locations over time, according to oneor more embodiments.

FIG. 38 is a graphical representation of pathogen survival rates overtime as they pass through the fluid heating system.

DETAILED DESCRIPTION

The present disclosure, in some embodiments, relates to a fluid heatingsystem for heating and/or thermal pasteurization of water. Inparticular, the fluid heating system may include an elongate parabolicmirror for focusing sunlight on a focal point or focal axis. A fluidheating tube may be arranged along the mirror and along the focal axisof the mirror. Water may be controllably passed through the heating tubeat a calibrated rate, dependent on time and temperature, to inactivatepathogens and create potable water. The fluid flow may be controlled bya thermally actuated valve particularly adapted to control pulsing flowand prevent contaminated water from passing through the valve. Stillfurther, the system may include a unique solar tracking system allowingfor tracking of the sun or other tracking processes with very low powerusage and high precision.

The systems, devices, and mechanisms described herein may allow forthermal heating and/or thermal pasteurization of water in remote areasof the world or in conditions of power loss, catastrophic event, war, orother situations. The system may do so substantially automatically, withlittle to no human interaction and little to no reliance on publicutilities, networks, or other utility, electrical, information, or otherinfrastructure. The system may include its own power source that may becapable of sustaining the operation of the system for extended periodsof time, and without connection to exterior power sources. The trackingsystem provided on the system may be used for solar tracking, such asfor the present device, or it may be used to track other items such assatellites, planets, or other objects having known or identifiablepositions relative to the position of the device. Various purposes mayexist for tracking of these or other devices or objects. Still otherimplementations of the present system or one or more of its devices ormechanisms may be provided.

Referring to FIG. 1, a perspective view of a fluid heating system 100 isshown. On a system level, the fluid heating system 100 may include asolar collection system 102, a fluid control system 104, a supportstructure 106, and a tracking system 108. The solar collection system102 may be configured for collecting and focusing solar energy at afocal point or a focal axis 103. The fluid control system 104 may beconfigured for storing fluid to be treated, treating the fluid bytransporting the fluid along the focal axis 103, and storing the treatedfluid. The support structure 106 may be configured for operablysupporting the solar collection system and one or more portions of thefluid control system. The tracking system 108 may be configured formanipulating the support structure 106, or portions thereof, therebyadjusting the position and orientation of the solar collection system102 and one or more portions of the fluid control system 104 in a mannerthat allows for efficient collection of solar energy and efficientheating of fluid.

Solar Collection System

With reference to FIGS. 2 and 3, the solar collection system 102 mayinclude a frame 110, a reflective element 112, and one or more uprightfluid control support elements 114. The frame 110 may be configured todefine the size and shape of the solar collection system 102 and toprovide a framework for the reflective element 112. The reflectiveelement 112 may be configured to receive sunlight or other radiation andreflect that sunlight or other radiation toward a common focal point oraxis 103. The upright fluid control support elements 114 may beconfigured for supporting the fluid heating element of the fluid controlsystem 104 at a substantially rigid position relative to the reflectiveelement 112 and, in particular, at the focal point or along the focalaxis 103. Each of the particular elements of the solar collection system102 may be described in more detail below.

Referring now to FIG. 4, the frame 110 may include a plurality oflaterally extending ribs 116 and a pair of longitudinally extendingrails 118. The ribs 116 may be configured to define a parabolic or othershape and provide spaced apart support of the reflective element 112along its length. The rails 118 may be configured to provide support andinward acting resistance along the edges of the reflective element 112.

Referring to FIG. 5, the ribs 116 may be in the form of a bar, plate,angle, tube, pipe, or other substantially elongate element having acurved shape or surface for defining the shape of the reflectiveelement. In one embodiment, the ribs may include a top surface 120having a parabolic or other curved shape. In some embodiments, the topsurface 120 may be due to the rib being formed or shaped. In otherembodiments, the top surface 120 may be created by cutting the shapeinto the rib. In some particular embodiments, the ribs 116 may be plateelements configured to be arranged on edge and the top surface 120 andbottom surface 122 may be defined by substantially parallel curvesoffset from one another defining a rib depth 124. The ribs 116 may havea thickness 126 of approximately 1/16 inch to approximately ¼ inch, orapproximately ⅛ inch to approximately 3/16 inch. Still other thicknessesmay be provided. The ribs 116 may have a depth 124 ranging fromapproximately ¼ inch to approximately 4 inches, or approximately ½ inchto approximately 2 inches, or approximately ¾ inch to approximately 1inch. The ribs 116 may have a length 128 dependent on the size of thesolar collection system 102 and may range from approximately 6 incheslong to approximately 10 feet long, or approximately 1 foot toapproximately 6 feet, or from approximately 2 feet to approximately 4feet.

The curvature of the top surface 120 or the portion engaging the backside of the reflective element 112 may be parabolic. In someembodiments, the curvature may be based on a function such as f(x)=x².In other embodiments, the curvature may be based on a function such asf(x)=x²−mx. The focal axis 103 of the reflective element 112 may bebased on the curvature of the ribs 116 and may range from approximately6 inches to approximately 8 feet, or approximately 1 foot toapproximately 4 feet, or approximately 2 feet to approximately 3 feet,or approximately 24 inches to approximately 26 inches above the vertex130 of the ribs, for example.

Referring to FIGS. 3 and 4, the ribs 116 may be arranged along the backside of the reflective element 112, may engage and be supported by thesupport structure 106, and may support the reflective element 112 inspaced apart relation. In particular, the ribs 116 may be spaced alongand secured to the spine element of the support structure 106 with abracket, tab, or other connecting element suitable for bolting the ribs116 to the spine or a welded connection may be used.

With reference to FIG. 6, like the ribs 116, the longitudinal extendingrails 118 may be in the form of a bar, plate, angle, tube, pipe, orother substantially elongate element. However, in contrast to the ribs116, the rails 118 may have a substantially straight shape for extendingalong the side of the reflective element 112, for resisting lateral andoutward motion of the reflective element 112, and for protecting theedge of the reflective element 112. In some particular embodiments, therails 118 may be angle elements having an angle-shaped cross-section.The angle may be arranged with one leg of the angle directed inwardlytoward the reflective element 112 and the other leg of the angledirected downwardly alongside the edge of the reflective element 112.That is, for example, the inwardly extending leg may be placed along theedge of the reflective element 112 and on the top surface of thereflective element 112 and the downwardly extending leg may extend downpast the reflective element 112. As the rail 118 extends along thereflective element 112 and passes by the ends of the ribs 116 spacedalong the structure, the rails 118 may be secured to the ribs 116. Assuch, any outward force from the compressively shaped reflective element112 may be resisted by abutment with the downwardly extending leg of therail 118 and its securement to the ribs 116.

The legs of the angle-shaped rail may have a thickness of approximately1/16 inch to approximately ¼ inch, or approximately ⅛ inch toapproximately 3/16 inch. Still other thicknesses may be provided. Thelegs of the angle may range from approximately ½ inch to approximately 8inches, or approximately ¾ inch to approximately 2 inches, orapproximately 1 inch to approximately 1½ inch. Still other angle sizesmay be provided and the legs of the angle may be the same or different.

Referring now to FIG. 7, the reflective element 112, which may besubstantially flat in an unassembled condition, may be placed,positioned, or arranged on top of the frame 110 and it may be presseddownwardly into the trough-shaped frame 110. Along the ends of thereflective element 112, keeper strips may be placed on top of thereflective element 112. Fasteners may extend through the keeper stripsand into one or more ribs 116 arranged below the end of the reflectiveelement 112. These keeper strips, together with adhesive between theback of the reflective element 112 and the ribs 116, and the resistancefrom the rails 118 may all function together to secure the reflectiveelement 112 in position on the frame 110.

The reflective element 112 may include a membrane, film, sheet, or otherrelatively flat element having an upper and a lower surface where theupper surface is relatively, substantially, or highly reflective. Insome embodiments, the reflective element 112 may include a series ofplies or layers adhered together to form the reflective element. In someembodiments, the reflective element may be a generally flat element inan unassembled condition and the relatively flat element may be held ina substantially curved and/or parabolic shape by the frame portion 110.In other embodiments, the reflective element 112 may be fabricated tohave a curved and/or parabolic shape on its own without the frameportion.

In some embodiments, the reflective element may include a plurality oflayers. In some embodiments, one layer may be a reflective film or layersuch as a 3M solar film or other all-polymeric mirror film or partialpolymeric mirror film. In some embodiments, the film may be wavelengthselective. In embodiments, the film may be a high reflectivity, noscatter type film. Still other reflective films may be used.

The film may be laminated onto a backing material to provide anincreased level of rigidity and/or uniformity and to provide scratchresistance and other protection during shipping. That is, the reflectivefilm material may be relatively thin and flexible and may be akin to apaper, plastic film, or other relatively flexible and foldable material.In contrast, while remaining formable, the backing material be a morerigid and yet flexible material. In some embodiments, the backingmaterial may include a relatively thin gauge material such as a plastic,metal such as aluminum, steel, stainless steel, or other metal, oranother thin gauge material may be provided. In some particularembodiments, the backing material may include stainless steel materialhaving a gauge ranging from approximately 36 gauge to approximately ¼inch, or from approximately 30 gauge to approximately ⅛ inch, or fromapproximately 28 gauge to approximately 20 gauge, or a thickness ofapproximately 21, 22, 23, 24, 25, 26, or 27 gauge may be used. The gaugeselected may be selected to arrive at a low weight system that alsoprovides for a substantially flat surface for the reflective film thatis also substantially dent resistant.

The several layers of the reflective element 112 may be laminatedtogether to form the reflective element 112. In some embodiments, theseveral layers may be laminated as a flat or substantially flat sheet.In some embodiments, the layers may be laminated with an adhesive suchas a pressure sensitive adhesive or other adhesive.

Turning now to the upright fluid control support elements 114, as shownin FIG. 8, these elements may be positioned on each end of the frame 110and may be configured to support a portion of the fluid control system104. In particular, these elements may be configured to support thefluid heating element and position the fluid heating element along thefocal axis 103 of the reflective element 112.

The upright fluid control support elements 114 may be secured to theribs 116 of the frame 110 at the end of the frame 110 or may serve as arib 116 at each end. That is, one or more upright fluid control supportelements 114 may be positioned at each end and may extend upwardly at ornear the vertex of the curvature of the reflective element 112 and up toor near the position of the focal axis 103. The upright fluid controlsupport element 114 may be a plate, pipe, tube, angle, or other shape.In some embodiments, as shown in FIGS. 2 and 3, the upright fluidcontrol support element 114 may include a tube guide 132 for incomingand effluent lines at the end of the system where the untreated water isentering the system and where the potable water is exiting. In someembodiments, the tube guide 132 may begin near the bottom of the uprightelement 114 and extend to a position at or near the top. In someembodiments, the tube guide 132 may be insulated to as to protectagainst user injury and/or exposure to relatively hot lines due toexiting hot water.

The above-described solar collection assembly 102 may includesubstantially flat elements, which may be useful for purposes ofshipping. That is, the frame 110 including the ribs 116 and thelongitudinal rails 118, the reflective element 112, and the uprightfluid support elements 114, may include substantially flat, plate-likeor substantially plate-like elements. For example, the ribs 116, whilecurved, may be plate-like and, as such, when unassembled and laid ontheir side, may be substantially flat. Similarly, the longitudinal rails118 may also be plate-like or substantially plate-like in the form ofangles, for example. The reflective element 112 may be a laminated filmand, as such, without support by the frame, the reflective element 112may be substantially flat. In addition, the upright fluid supportelements 114 may also be plate-like or substantially plate-like allowingthem to lay substantially flat when disconnected from the frame 110.

When the solar collection system 102 arrives at its location, it may beassembled to form the solar collection system 102 as shown in FIGS. 1-3.The solar collection system 102 may be positioned atop or supported bythe support structure 106 described in more detail below.

Fluid Control System

As mentioned, the fluid control system 104 may be configured for storingfluid to be treated, treating the fluid by transporting the fluid alongthe focal axis 103, and storing the treated fluid. It should beappreciated that while the fluid control system 104 is being describedin conjunction with the solar collection system 102, the fluid controlsystem 104 may be used with alternative sources of heat. For example,the fluid control system 104 may be arranged for exposure to burningfuels such as coal, wood, propane, natural gas, or other fuels. In stillother embodiments, the fluid control system 104 may be arranged forexposure to electrical sources of heat, such as electric heaters, heattraces, or other sources of electrical heat. The fluid control system104 may be used with any source of heat and functions to control theflow of fluid through the system based on the temperatures the fluidreaches. As such, the amount or type of heat supplied, while relevant tothe rate at which the system may supply potable water or other treatedfluid, is not limited to the solar collection system 102 mentioned.

As shown in FIG. 9, the fluid control system 104 may include acollection reservoir 134, a feed line 136, a fluid heating element 138,a flow control assembly 140, a return line 142, a preheat heat exchanger144, an effluent line 146, and a treated fluid reservoir 148. Thecollection reservoir 134 may be configured to collect water or otherfluid from one or more sources and hold the fluid until the system isavailable to treat the fluid. The feed line 136 may be configured tocarry the fluid from the collection reservoir to the fluid heatingelement. The fluid heating element 138 may be configured to exposeand/or hold the fluid in position relative to a heat source. The flowcontrol assembly 140 may control the flow of the fluid through the fluidheating element 138 such that the fluid is sufficiently exposed to theheat source. The return line 142 may be configured to receive the fluidfrom the control valve 140 and carry the fluid along the fluid heatingelement 138 toward the entrance to the fluid heating element 138. Thepreheat heat exchanger 144 may be configured to thermally expose thetreated fluid from the return line 142 to the incoming fluid from thefeed line 136 so as to preheat the incoming fluid as it enters the fluidheating element 138 and to simultaneously cool the treated fluid. Theeffluent line 146 may carry the fluid away from the system to thetreated fluid reservoir 148. The treated fluid reservoir 148 may beconfigured to collect treated fluid and store the treated fluid until itis used.

With continued reference to FIG. 9, the collection reservoir 134 may bein the form of a tank. The tank may include most any type of tankincluding pre-fabricated tanks or tanks constructed on site. In the caseof on-site constructed tanks, the tank may be a flat bottom concretetank or a steel tank of bolted or welded construction and the tank mayinclude a liner. In some other embodiments, the tank may be an elevatedconcrete tank, an elevated steel tank of bolted or welded construction,or a composite elevated tank, for example, may be provided. In otherembodiments, the collection reservoir 134 may be a polypropylene,polyethylene or other polymeric material suitable for collecting andstoring water or other fluid. In still other embodiments, the collectionreservoir 134 may be a fiberglass material, wood material, or othermaterial. Still other types of tanks may be contemplated and used.

The collection reservoir 134 may collect water or other fluid from oneor more sources. For example, the reservoir 134 may collect water fromlakes, rivers, public reservoirs, public or private distribution systemsand the like. In some embodiments, the collection reservoir 134 may begravity fed by these systems and may include a shutoff or other valvefor avoiding overflow situations. In other embodiments, the collectionreservoir 134 may include a pump arranged in a water or fluid sourcethat may pump the water to the collection reservoir 134 when thereservoir is low on water or fluid. In some embodiments, the collectionreservoir 134 may collect rain water and may be used in conjunction witha land basin or other basin configured to collect rainwater and/or otherrunoff.

The reservoir 134 may be a single tank or multiple tanks may beprovided. For example, where multiple sources of fluid or water areavailable, but are not conducive to feeding a single tank, multipletanks may be used. In some embodiments, multiple systems may rely on acentralized or community tank. For example, a city, township, village,or other group of users may rely on a single tank or a series of tanksall of which may be positioned to take advantage of a particular sourceof water or fluid.

In some embodiments, the collection reservoir 134 may be positionedrelative to the system so as to gravity feed the system. As such, thecollection reservoir 134 may be located at an elevated position relativeto the system such as up on a hill, on a structural pedestal, on a roof,or on another elevated structure or land formation. Where the locationof collection is not in an elevated position relative to the systemtreating the water, multiple tanks may be provided. For example, a firstcollection reservoir 134 may be provided at the location conducive tocollection and a pump may be provided to pump the water to a second tankor reservoir 134 conducive to feeding the system. In some embodiments,the pump may be run at off peak hours or otherwise used in a manner toreduce costs incurred by using the system.

It should be appreciated that while a tank or series of tanks have beenmentioned, the collection reservoir 134 may also take several otherforms such as a basin, a lake, a river, an open pit, an open trough, orother container, structure, or land formation that is capable of atleast temporarily holding water or other fluid. That is, in addition toother types of tanks, where the system is being used at or near arelatively continuous either static or flowing source of water or fluid,the collection reservoir 134 may take the form of such source of wateror fluid.

A feed line 136 is also shown in FIG. 9. The feed line 136 may be influid communication with the collection reservoir 134 so as to provide acontinuous, substantially continuous, or periodic supply of fluid orwater to the fluid heating element 138. The feed line 136 may be tappedinto the collection reservoir at or near the bottom, for example, so asto receive water or fluid from the collection reservoir 134 unless oruntil the collection reservoir 134 is nearing an empty condition. Thefeed line 136 may be tapped in slightly above the bottom to allow anarea in the collection reservoir 134 for sediment or other debris tosettle out without flowing into the system. The feed line 136 may extendfrom the collection reservoir 134 to the fluid heating element 138 viathe preheat heat exchanger 144. The feed line 136 may be apolypropylene, polyethylene, or other polymeric material or anothermaterial may be used. The feed line 136 may be sized to accommodate theflow of fluid or fluid to the system without overly constraining flowand, as such, the feed line 136 may have a diameter and/orcross-sectional flow area reasonably similar to the diameter orcross-sectional flow area of the fluid heating element 138. In someembodiments, the feed line 136 may be a ½ inch, ¾ inch, 1 inch, 1½ inch,2 inch, or 3 inch line, for example. In still other embodiments, othersize feed lines 136 may be used.

Referring now to FIG. 10, the fluid heating element 138 is shown. Thefluid heating element 138 may include an elongated flow element 150 anda housing 152. The elongated flow element 150 may be configured totransport the water or fluid along the focal axis 113 of the solarcollection system 102 or along another heat source and cause the wateror other fluid to be heated. The housing 152 may be configured forinsulating a portion of the elongated flow element 150. The housing 152may also be configured for controlling or reducing convective flow ofair relative to the elongated flow element 150.

As shown in FIG. 11, the elongated flow element 150 may be in the formof a pipe, tube, or other lumen providing shape. The elongated flowelement 150 may include an exposed side and a non-exposed side where theexposed side is the side exposed to the heat source and the non-exposedside is the side opposite the heat source. In some embodiments, theelongated flow element 150 may be a symmetrical shape having a wallthickness that is substantially consistent around its perimeter. Inother embodiments, the exposed side may have a wall thickness less thanthe non-exposed side. The elongated flow element 150 may be constructedof a conductive material so as to conduct the heat from the heat sourceand transfer that heat to the water or fluid flowing therethrough. Whileconductive, the elongated flow element 150 may also be constructed of amaterial that can withstand exposure to extreme heat without excessivelevels of deformation, elongation, and the like. In some embodiments,the elongated flow element 150 may include a coefficient of thermalexpansion ranging from approximately 10×10⁻⁶ l/C to 200×10⁻⁶ l/C. Insome embodiments, the elongated flow element may include a melting pointranging from approximately 160 degrees C. to approximately 1500 degreesC. In some embodiments, the elongated flow element 150 may include asteel, stainless steel, lead, copper, or other pipe, for example. Theelongated flow element 150 may be coated with a high emissivity coatingto allow the elongated flow element 150 to effectively absorb the energyfocused on it by the solar collector 102.

The elongated flow element 150 may engage the preheat heat exchanger 144at an inlet end of the elongated flow element 150. The elongated flowelement 150 may engage the flow control assembly 140 at an outlet end ofthe elongated flow element 150. At each of these connections, anexpansion joint 154 may be provided to allow for at least some of theexpansion of the elongated flow element 150 relative to the uprightsupport elements 114 that are supporting the system the preheat heatexchanger 144 and the flow control assembly 140. As shown in FIGS. 13Aand 13B, the expansion joint 154 may include an annular resilient washeror o-ring seated in an annular space where the annular washer has anouter and inner diameter that is the same or similar to the outer andinner diameter, respectively, of the elongated flow element 150. Assuch, the annular washer may abut each end of the elongated flow element150 and maintain a seal against the end of the elongated flow element150 while allowing fluid to flow therethrough. The resilient washer maybe constructed from a temperature resistant material that maintains itsresiliency under extreme temperature conditions. In some embodiments,the resilient washer may include high temperature Viton or otherfluorocarbon elastomer. Still other materials for the resilient washeror other expansion joint elements may be provided. A same or similardetail may be provided for each end of the return line 142.

The housing 152 is shown in FIG. 12 and may be arranged on the elongatedflow element 150 and may extend substantially along the full length ofthe elongated flow element 150. As mentioned, the housing 152 may beconfigured to insulate a portion of the elongated flow element 150 andmay be configured to control convective air flow around the elongatedflow element 150. That is, the housing 152 may be configured to reduceheat losses from the elongated flow element 150 that may occur were theelongated flow element 150 to be unprotected in this regard. Inaddition, the housing 152 may cover or protect portions of the elongatedflow element 150 (i.e., sides and top) such that exposed surfaces thatcould be touched by users or otherwise contacted by living tissue arenot as hot, thereby reducing burn risk.

The housing 152 may be arranged on the non-exposed side of the elongatedflow element 150. As shown, the housing 152 may encapsulate, engulf, orotherwise substantially fully cover the non-exposed side of theelongated flow element 150. The housing 152 may extend partially orsubstantially fully along the length of the elongated flow element 150.That is, portions of the elongated flow element 150 may extend beyondthe housing 152 to engage the preheat heat exchanger 144 at the inletend or the control valve assembly 140 at the outlet end, but other areasof the elongated flow element 150 may be fully covered by the housing152. The housing 152 may be adhered to the elongated flow element 150with a heat resistant adhesive, such as, for example, a two-part epoxyor high temperature silicon.

In some embodiments, as shown, the housing 152 may extend around thesides of the elongated flow element 150 to about the mid-depth of theelement 150. In the case of a pipe, for example, the housing 152 mayextend half way around the pipe thereby exposing the bottom half of thepipe to the heat source while protecting the upper half of the pipeagainst heat loss and providing protection against burns. The housing152 may include a substantially insulating material such as, forexample, a ceramic material or a glass pipe with evacuated interior.Other materials useful as a housing material may include insulatingfibers, composite materials, or high temperature plastics. Still othermaterials may also be used. The housing 152 may have a substantiallyround, rectangular or other shape. That is, the bottom portion of thehousing 152 may conform to the outside surface shape of the elongatedflow element 150 and the remaining portion of the housing 152 may have aparticular shape such as a round or rectangular shape as suggested. Insome embodiments, the housing 152 may be sized so as to encapsulate orinclude the return line 142 as well as the non-exposed side of theelongated flow element 150. In some embodiments, insulating material maybe arranged between the return line 142 and the elongated flow element150 so as to reduce the escape of energy from the elongated flow element150 into the return line 142.

In some embodiments, in addition to insulating the elongated flowelement 150, the housing 152 may extend laterally away from the sides ofthe elongated flow element 150 to provide a sort of hood or awning 156adjacent the elongated flow element 150. The hood or awning 156 may beconfigured to resist or prevent flow of air or other fluid upward from abottom side of the elongated flow element 150. This resistance to airflow may reduce the amount of energy that is lost from the elongatedflow element 150 due to convective air currents. In some embodiments,the hood or awning 156 may extend laterally away from the elongated flowelement 150 a distance related to the size of the elongated flow element150. For example, the hood or awning 156 may extend laterally away fromthe elongated flow element 150 an awning distance 158 ranging fromapproximately ¼ of the diameter of the elongated flow element to 4 timesthe diameter. In other embodiments, the distance may range fromapproximately ½ the diameter to 2 times the diameter, or fromapproximately 1 times the diameter to 1½ times the diameter. The awningor hood 156 may extend substantially horizontally (i.e., along thelateral centerline of the elongated flow element 150 or pipe) away fromthe elongated element 150 or the awning or hood 156 may be angledslightly upward or downward relative to the horizontal.

Turning now to FIGS. 14-16, the flow control assembly 140 may providecontrolled flow of treated fluid from the elongated flow element 150 tothe return line 142. In some embodiments, the flow control assembly 140may be positioned downstream of the fluid heating element 138 andupstream of the treated water reservoir 148. In one embodiment, the flowcontrol assembly 140 may be positioned at an end of the solar collectoropposite the entry end. The flow control assembly 140 may be configuredto allow pasteurized fluid to pass through the assembly 140 and may helpto prevent unpasteurized fluid from passing through, thereby avoidingcontamination of fluid present in the treated water reservoir 148. Suchcontrolled flow of the treated fluid is desirable in order to regulatefluid pressures in the system and also to monitor temperature of thefluid entering the return line 142 in order to reduce, and mostpreferably prevent, the chance of unpasteurized fluid being passed intothe treated water reservoir 148.

The flow control assembly 140 may comprise at least one thermostaticflow control valve 160 disposed between the elongated flow element 138and the return line 142. Each thermostatic flow control valve 160 maycomprise an operation temperature and a flow rate (i.e., the flow ratebeing dependent on the pressure in the system and the valve openingsize). The thermostatic flow control valve 160 may be biased in a closedposition. In the closed position, fluid may be prevented from passingfrom the elongated flow element 150 to the return line 142 through thethermostatic flow control valve 160. When the temperature of the fluidmeets or exceeds the operating temperature of the thermostatic flowcontrol valve 160, the valve 160 may open to allow fluid to pass throughthe valve 160. In some embodiments, the valve 160 may begin to open atthe operating temperature and may continue to open further astemperatures increase. When the valve 160 is open fully, fluid may flowthrough or passed the valve 160 at the valve flow rate from theelongated flow element 150 through the thermostatic flow control valve160 to the return line 142 and ultimately into the treated waterreservoir 148.

Use of a single thermostatic flow control valve may, in someembodiments, create a risk of introducing unpasteurized fluid into thetreated water reservoir 148. That is, when a thermostatic valve opens,water that has been heated in the elongated flow element 150 passesthrough the valve and, as such, water in the elongated flow element 150continues to flow and spend less time in the elongated flow element 150.The flowing water may have a reduced temperature than the water or fluidinitially providing the operating temperature because of the lesseramount of time the now flowing fluid spent in the elongated flow element150. As the valve is exposed to the cooler water, the valve may begin toclose or fully close. However, the reaction time of the valve inconjunction with the flow rate of the water may be such thatunpasteurized water passes through the thermostatic valve before it canclose. This type of pulsed flow for a single thermostatic valve mayprovide risk of contaminating the downstream aspects of the system andthe treated water.

In order to provide a system with flexibility to accommodate severalflow rates and temperatures while lowering the risk that untreated fluidwill escape through the system, some embodiments may include a pluralityof thermostatic valves 160. The plurality of thermostatic control valves160 may include different operation temperatures and may also havediffering flow rates. This arrangement may include valves that haveoperating temperatures that are lower having lower flow rates whilevalves that have higher operating temperatures may have higher flowrates. The several valves acting in concert may reduce the risk ofunpasteurized fluid passing through the control valve assembly 140 andcontaminating the downstream elements and the treated water reservoir148.

FIG. 14 shows a schematic view of one embodiment of flow controlassembly 140. The flow control assembly of FIG. 14 comprises a pluralityof flow control valves 160, an inlet 162 at a first end of the flowcontrol assembly 140, and an outlet 164 at a second end of the flowcontrol assembly 140. In at least one embodiment, as shown in FIG. 14,the flow control assembly 140 comprises five flow control valves 160,although any number of suitable valves for the assembly may be used. Thenumber of valves 160 may depend on the average or median flow rate ofthe system, the solar heating rate, and the range of pasteurizationtemperatures. Each flow control valve 160 may have an operationtemperature and a flow rate, and in at least one embodiment theoperation temperature may differ from at least one other flow controlvalve 160 in the assembly 140. Each flow control valve 160 may be biasedin the closed position. In some embodiments, as shown, the flow controlvalves 160 may be disposed relative to one another in a parallelconfiguration. In other embodiments, at least one flow control valve 160may be disposed relative to another flow control valve in a seriesconfiguration. The inlet 162 may be in fluid communication with theelongated flow element 150, and the outlet 164 may be in fluidcommunication with the return line 142. Fluid may enter the flow controlassembly 140 from the inlet 162. Based on the temperature of the fluid,one or more of the flow control valves 160 may open based on theirrespective operating temperatures, and the fluid may pass through theoutlet 164. If the fluid entering the flow control assembly 140 is belowthe operating temperature of all of the flow control valves 160, all ofthe control valves 160 may remain closed such that fluid does not passthrough the outlet 164. The plurality of valves 160 and the operatingtemperature of each may be selected to ensure that the temperaturesexperienced by the fluid as it passes through the elongated flow element150 and the time it remains at those temperatures is sufficient topasteurize the fluid. A model relating to inactivation of pathogens andthe temperatures and times created by the present system is discussedbelow. This system may allow for the flow of the fluid in the system tobe relatively constant over time and reduce or even eliminate pulsedflow.

FIG. 15 shows an exploded view of one embodiment of a flow controlassembly 140. FIG. 16 shows a cross-sectional view thereof. The flowcontrol assembly 140 of FIGS. 15-16 may include a housing which maycomprise a face 168 and a body 170 defining a chamber 172 and one ormore flow channels 174. The assembly may also include a plurality offlow control valves 160 disposed at least partially within the chamber172. In some embodiments, as shown, the flow control assembly 140 mayfurther comprise a degassing valve 176 for releasing any excess fluidpressure that may build up within the assembly. In some embodiments, asshown, the flow control assembly 140 may further comprise flush portswithin the body 140 for cleaning any contamination within the chamber172 or the flow channels 174 and plugs that seal the flush ports. Asshown in the embodiment of FIG. 15, the flow control assembly 140 mayinclude three flow control valves 160 disposed within the body 170 ofthe housing. However, any number of suitable valves for the assembly maybe used. The three flow control valves 160 may be arranged in parallelwithin the housing 170. The housing may protect the flow control valves160 from the elements. In addition to protecting the flow control valves160, the housing may provide insulation so as to prevent or reduce heatloss from the fluid within the flow assembly 140. In at least theembodiment shown, the face 168 may be removably connected to the body170. In some embodiments, the face 168 of the housing mates directlywith the fluid heating element 138. In at least the embodiment shown,the face 168 may include a first opening defining the inlet 162, and theface 168 may include a second opening defining the outlet 164. The inlet162 may provide fluid communication between the chamber 172 and theelongated flow element 150, and the outlet 164 may provide fluidcommunication between the one or more flow channels 174 and the returnline 142. In at least one embodiment, the housing may include a pressuredrop hole for each flow control valve 160 where the position and size ofthe pressure drop hole may be dependent upon the temperature setting ofthe flow control valve 160.

In some embodiments, the flow control valves 160 may comprisethermostatic control valves 160 or other mechanically actuated flowcontrol valves 160. In at least the embodiment shown in FIGS. 15-16,each flow control valve 160 comprises a thermostatic element 178, avalve tube 180, a valve plunger 182, and a spring 184. In at least oneembodiment, the thermostatic element 178 is disposed within the chamber172 and mechanically connected to the plunger 182, and the valve plunger182 is disposed within the valve tube 180. The thermostatic element 178may have an operating temperature, and the thermostatic element 178 maybe activated when the thermostatic element 178 comes into contact withfluid in the chamber 172 that meets or exceeds the operatingtemperature. The valve tube 180 and the valve plunger 182 work togetherto thermally actuate and allow fluid passage when a fluid reaches theoperating temperature of the valve 178. In at least one embodiment, theplunger 182 has an indentation which moves in a first direction as therespective thermostatic element 178 warms and in a second direction asthe respective thermostatic element 178 cools. The spring 184 biases thevalve plunger 182 into a closed position. In at least one embodiment thevalve tube 180 has a hole disposed within the sidewall of the valvetube, the hole being in fluid communication with the flow channel 174.When the indentation of the plunger 182 is aligned with the hole on thevalve tube sidewall, fluid passes from the chamber 172 into through theflow channel and passed the valve to the outlet 164. When the plunger182 is positioned so that the indentation is not aligned with the hole,fluid cannot pass from the chamber 172 into the flow channel 174. Insome embodiments, as the valve plunger 182 moves in either the firstdirection or the second direction, a portion of the hole may be alignedwith the indentation of the plunger 182 such that flow is restricted.

Each flow control valve 160 may have its own operating temperature andflow rate. In a preferred embodiment, the operating temperature for allflow control valves 160 within the flow control assembly is below theboiling point of the fluid (e.g. for water, 100 degrees C.). In oneembodiment, the flow control valves 160 may all have the same operatingtemperature setting such that when the fluid reaches that temperaturethe valves are open, which may result in a pulsed flow of the fluid. Ina preferred embodiment, the operating temperature and/or flow rate foreach flow control valve 160 differs from at least one other flow controlvalve 160 in the assembly. This may provide for more stable flow of thefluid within the system as opposed to a pulsed flow. In at least oneembodiment, a first control valve 160 may have a first operatingtemperature. The first control valve 160 may also have a first flowrate. The first control valve 160 may be biased in the closed position.A second control valve 160 may have a second operating temperaturegreater than the first operating temperature of the first control valve160. In some embodiment, the second control valve 160 may also have asecond flow rate greater than or different from the first flow rate. Inembodiments having a third control valve 160, the third control valve160 may have a third operating temperature greater than the secondoperating temperature of the second temperature control valve 160 andgreater than the first operating temperature of the first temperaturecontrol valve 160. In at least one embodiment, the third operatingtemperature may be below the boiling point of the fluid (e.g. for water100 degrees C.). In some embodiments, the third control valve 160 mayhave a third flow rate greater than or different from the second flowrate and greater than or different from the first flow rate. The flowrates through the system may be dictated by the valve settings and thesupplied pressure (or height of the fluid supply tank). For residentialapplications with roof-top water vessels, for example, and high incidentsolar energy, the flow rates may be approximately one gallon per minute,for example, or more. In some embodiments, the operating temperatures ofthe control valves may include 78 degrees C., 85 degrees C., and 90degrees C. In still other embodiments, the operating temperatures of thecontrol valves may include 50 degrees C., 55 degrees C., and 60 degreesC. In still other embodiments, the operating temperatures of the controlvalves may include 60 degrees C., 70 degrees C., and 80 degrees C. Asmay be appreciated, the higher temperature settings of the controlvalves may reduce the flow rate of the system overall, but may increasethe treatment temperature. The model discussed below with knowledge ofthe pathogens that are present may be used to select suitable operatingtemperatures for the valves so as to ensure suitable treatment and toalso give consideration to efficient use of the solar energy byproviding relatively fast flow rates.

In at least one embodiment, the flow control valves 160 may be arrangedto act additively. That is, when a first control valve 160 opens andthen a second one opens, the flow rate of the first valve 160 may besupplemented by the second valve 160 such that the flow rate increasesbased on the additional flow allowed by the second valve 160. In someembodiments, when the temperature of the fluid reaches the firstoperating temperature, the first control valve 160 may open to allowfluid to pass through the chamber 172 to the flow channel 174 at thefirst flow rate. When the temperature of the fluid reaches the operatingtemperature of the second control valve 160, the second control valve160 may open to allow fluid to pass through the chamber 172 to the flowchannel 174 at a second flow rate. With fluid flowing through both theof the first and second valves 160, the resulting flow to the returntube 142 may be a combination of the flow rate of the first and secondvalves 160. Where the system has at least three control valves 160, whenthe temperature of the fluid reaches the operating temperature of thethird control valve 160, the third control valve 160 may open to allowfluid to pass through the chamber 172 to the flow channel 174 at thethird flow rate. As the temperature of the fluid declines below thethird operating temperature, the third valve 160 may close and lessfluid may be allowed to flow. As the temperature of the fluid furtherdeclines below the second operating temperature, the second valve 160may close and less fluid may be allowed to flow. If however, thetemperature falls below a threshold temperature, all of the controlvalves 160 may then return to their biased closed position.

In still other embodiments, the distance between the temperature chamber172 and the flow control portion of the valve 160 may be determined inan effort to protect against untreated water flowing through the system.That is, this distance may be selected together with flow rates andvalve closing times such that when temperatures drop below the operatingtemperature of a given valve 160, the valve 160 has sufficient time toclose before fluid or water below the operating temperature reaches theflow control.

As mentioned, the flow control assembly 140 may also include a degassingvalve 176. As shown in FIG. 16, the degassing valve 176 may be arrangedwithin the flow control assembly 140 at an upper location where gases inthe system will work their way to the valve location. The degassingvalve 176 may be configured to purge air, steam, or other gas in thesystem on startup, when there is an intermittent water source, and asgas develops within the system such as when water vapor builds up duringboiling, for example. As shown, the degassing valve 176 may be arrangedon the control valve 160 assembly, for example.

As shown in more detail in FIGS. 18A-18C, the degassing valve 176 mayinclude a float 186, a cap 188, and a linkage 190. The cap 188 may be arelatively rigid element configured for sealingly securing to the fluidcontrol assembly 140 over an opening. That is the control valve assembly140 may have an opening on its surface that is in fluid communicationwith the fluid pathway extending through the control valve assembly 140.The opening in the control valve assembly 140 may be arrangedsubstantially near the top of the assembly 140 in a position where gasesmay naturally propagate, for example. The cap 188 of the degassing valve176 may be configured to be secured over the opening in a sealed fashionto prevent leakage of fluid from the control valve assembly 140. Whenthe cap 188 is secured over the opening, a chamber 192 may be defined inthe control valve assembly 140 over which the cap 188 is arranged. Thecap 188 may include an orifice 194 for allowing the release of gasesfrom the system.

The float 186 of the degassing valve 176 may be configured forarrangement in the chamber 192 formed by the control valve assembly 140188 and the cap 188. The float 186 may be sized and shaped such that itmay move substantially freely upward and downward within the chamber 192below the cap 188. In some embodiments, the float 186 may be shaped likea piston, for example, and may be substantially cylindrical. The float186 may be a two piece assembly as shown having a main body portion anda base portion or the float 186 may be a single piece float 186. Thefloat 186 may be constructed of substantially light-weight material andwhen assembled with the internal cavity shown, may have a weight andvolume that provide for a density less than water so that it floats whenwater or other fluid is present in the chamber 192.

The float 186 may be operable relative to the cap 188 by way of alinkage 190. As shown, a linkage 190 may be provided that secures thefloat 186 to the cap 188 and articulates between the float 186 and thecap 188 as the float 186 moves upward and downward in the chamber 192.It is to be appreciated that when water is present in the chamber 192,the float 186 will rise in the water causing the float 186 to moveupward in the chamber 192. As shown in FIGS. 18B and 18C, the linkage190 may include a seal 196 for sealing the orifice 194 in the cap 188when the float 186 is moved to an upper position in the chamber 192 andrelative to the cap 188. The present linkage 190 may provide aparticularly strong sealing force on the cap orifice 194 due to thelinkage arrangement. That is, as shown in FIGS. 18B and 18C, when thefloat 186 is in the upper most position in the chamber 192, furtherupward motion of the float 186 may be resisted by the sealing stopper196 over the orifice. That is, when the float 186 is in the upper mostposition, the linkage 190 is in a fixed position forming a staticallydeterminate structure. As shown in the free-body diagram of FIG. 17, theforce on the end of the bottom linkage member 198 from the float 186 maycreate a compressive force in the strut 200. The compressive force inthe strut 200, may be higher than the float force because the strut 200is positioned along the bottom linkage 198 at a position closer to thepivot point A than the float connection. For example, the strut forcemay be approximately 4 times the upward force from the float. The strut200 may push upwardly on the upper linkage 202, which may be resisted bythe seal 196 being seated over the orifice 194. Once again, because thesealing stopper 196 is positioned along the upper linkage 202 at aposition closer to the pivot point B than the strut force, the forceapplied at the sealing stopper 196 may be much higher than the strutforce. For example, the force applied at the sealing stopper 196 may beapproximately 4 or 5 times the strut force. Accordingly, the sealingforce 196 in the degassing valve 176 may be approximately 16 to 20 timesthe force of the float 186. This type of linkage 190 may allow for arelatively small float 186 and/or a relatively high sealing force fromthe float 186.

Referring back to FIGS. 10 and 11, a return line 142 is shown. Thereturn line 142 may be in fluid communication with the flow controlassembly 140 and may redirect water or fluid back to the preheat heatexchanger 144. In some embodiments, the return line 142 may extendthrough the housing 152 of the fluid heating element 138 as shown and totake advantage of the insulating properties of the housing 152. In otherembodiments an alternative route may be provided and alternativeinsulation may be provided. It is to be appreciated that the fluidexiting the flow control assembly 140 may be at relative and/orextremely high temperatures. As such, the return line 142 may beconstructed from relatively heat resistant material such as metal,ceramic, composite materials, or high temperature plastic. Still othermaterial may be used. In some embodiments, the return line 142 may be atube, pipe, or other lumen-type element. In some other embodiments thereturn line 142 may lead to the housing 152 and terminate at a lumenformed in the housing 152 such that the lumen in the housing may carrythe fluid to the preheat heat exchanger 144.

It is to be appreciated that where a heat exchanger is not being used(i.e., in the condition of water heating) the return line 142 may leaddirectly to the treated water or fluid reservoir 148 or to a point ofuse rather than returning to the preheat heat exchanger 144. That is,where the system is implemented in a situation where the fluid is beingheated to produce hot water as opposed to being used to pasteurizewater, the step of preheating of the water may be omitted because theheat exchange operation sacrifices heat from the outflowing fluid.

Turning now to FIGS. 19A and 19B, the return line 142 may return thewater or fluid to the preheat heat exchanger 144. As shown, the preheatheat exchanger 144 may receive water or other fluid from the feed line136 as well as water or fluid from the return line 142. The preheat heatexchanger 144 may be configured to provide thermal communication betweenthese two fluids such that heat from the return line fluid may be usedto increase the temperature in the feed line fluid. In the case of awater pasteurization process, once the water is pasteurized, the heat inthe water may no longer be useful or helpful and, as such, it can beused to increase the temperature in the incoming water to give it a sortof head start on heating by utilizing otherwise wasted energy. That is,were the water in the return line 142 simply directed toward the treatedwater reservoir 148, such water would be placed in the reservoir 148 atan extremely high temperature only to sit in the treated fluid reservoir148 and have the heat dissipate wastefully. Moreover, the effluent line146 may be extremely hot if the treated fluid is not passed through theheat exchanger 144.

The heat exchanger 144 may include a front 204, back 206, and middlebody 208. The front 204 and back 206 bodies may be configured tosandwich the middle body 208 between them and maintain a substantiallyconstant and even sealing pressure on the middle body 208. The middlebody 208 may be configured to receive the return line fluid and the feedline fluid and thermally expose them to one another to transfer the heatfrom the return line fluid to the feed line fluid.

The front and back bodies 204, 206 may be substantially block-likeelements with a relatively large amount of mass. For example, in someembodiments, the front and back bodies 204, 206 may be substantiallythick relative to the middle body 208. The front and back bodies 204,206 may be substantially rectangular and may have a perimeter size andshape that is substantially the same or similar to the perimeter sizeand shape of the middle body 208. Accordingly, when the front and backbodies 206, 208 are assembled with the middle body 208, a block-likeelement having a thickness equal to the combined thicknesses of theseveral elements may be provided. In some embodiments, the plan viewsize of the front and back bodies 204, 206 may range from approximately1 inch to approximately 12 inches, or from approximately 2 inches toapproximately 8 inches or from approximately 4 inches to approximately 6inches. The thickness of the front and back bodies 204, 206 may rangefrom approximately ½ inch to approximately 4 inches or fromapproximately ¾ inch to approximately 2 inches or from approximately ¾inch to approximately 1¼ inches.

The middle body 208 may include a substantially plate-like elementconfigured for being sandwiched between the front and back bodies 204,206. The middle body 208 may have formed in each face a fluid pathway216 for routing fluid in a relatively or substantially tortuous pathway.In some embodiments, as shown, the fluid pathway 216 may include a roundand/or spiral type of pathway. It is to be appreciated that the pathwayson each face may be mirror images of one another such that fluid flowingthrough each of the pathways is substantially adjacent to the fluid onthe opposing side of the middle body 208 and separated only by thethickness remaining between the formed pathways 216. In someembodiments, the thickness between fluid pathways 216 on each side ofthe middle body 208 may range from approximately 28 gauge toapproximately inch or from approximately 21 gauge to approximately 1/16inch or from approximately 17 gauge to approximately 19 gauge. Stillother thicknesses may be provided and selected to reduce the thicknessas much as possible while accommodating reasonable fabricationtolerances and considering effects of wear, corrosion, or other effectsthat may create holes or perforations in the thin wall. While a spiralpathway is shown, it is to be appreciated that several other pathwaysmay be used such as a zigzag, switchback, or other arrangement. Thepathway 216 may be effective to provide for a long length in a smallamount of space so as to increase the amount of time that the twoflowing fluids are thermally exposed to one another. Moreover, thetortuous path may have a relatively high fluid mixing effect such thateach of the fluids on either side of the middle body 208 continually mixwith themselves, thus allowing for a better distribution of heat withineach fluid and, thus, better thermal exchange through the middle body.In some embodiments, the fluid on either side of the middle body 208 maybe configured to flow in the same direction as the fluid on the otherside or the fluid may flow opposite directions as compared to the fluidon the other side.

The front 204, back 206, and middle bodies 208 may be constructed fromthe same or different materials. In some embodiments, the front, backand middle bodies 204, 206, 208 may be constructed from a same orsimilar conductive material. In other embodiments, the front and backbodies 204, 206 may include substantially insulating materials so as toavoid dissipation of heat from the system. In contrast, the middle body208 may be made from relatively or highly conductive material so as toconduct heat from the return line fluid and transfer the heat to thefeed line fluid. In some embodiments, for example, the front and backbodies 204, 206 may include a ceramic or other insulating material andthe middle body 208 may include a metal such as steel or otherconductive material. In some embodiments, the middle body 208 may alsoinclude an insulating perimeter to resist heat loss out the sides of themiddle body 208.

It is to be appreciated that while the heat exchanger 144 has beendescribed as having three parts, manufacturing techniques may be used tomanufacture the heat exchanger 144 as a single part. For example,injection molding or additive manufacturing such as 3D printing mayallow for the heat exchanger 144 to be formed as a single piece. Stillother manufacturing methods and approaches may be used.

Turning back now to FIG. 9, an effluent line 146 is shown. The effluentline 146 may be in fluid communication with the preheat heat exchanger144 and the treated fluid collection reservoir 148. The effluent line146 may be tapped into the collection reservoir 148 at or near the top,for example. Like the feed line 136, the effluent line 146 may be apolypropylene, polyethylene, or other polymeric material or anothermaterial may be used. The effluent line 146 may be sized to accommodatethe flow of fluid from the system without overly constraining flow and,as such, the effluent line 146 may have a diameter and/orcross-sectional flow area reasonably similar to the diameter orcross-sectional flow area of the fluid heating element 138. In someembodiments, the effluent line 146 may be a ½ inch, ¾ inch, 1 inch, 1½inch, 2 inch, or 3 inch line, for example. In still other embodiments,other size effluent lines may be used.

The treated fluid collection reservoir 148 may be a closed sanitary tankconfigured to remain in a sanitary condition so as to avoidcontamination of the treated and/or pasteurized water or fluid. In someembodiments, for example, the treated water reservoir 148 may be astainless steel tank, a coated steel tank, a polyethylene,polypropylene, or other polymeric material. The treated fluid collectionreservoir 148 may be sized based on the output of the system and may besized based on one or more systems where more than one system isdirecting treated fluid to the tank. The treated fluid collectionreservoir 148 may include a pressure relief valve equalizing pressureswithin the tank and/or a breathing mechanism that allows air transfer,but resists and/or prevents entry of contaminants or pollutants, forexample.

The treated fluid collection reservoir 148 may be in fluid communicationwith a potable water distribution or supply system such that the potablewater may be used for drinking, cooking, or other purposes. In someembodiments, the collection reservoir 148 may include a spigot or otherdistribution mechanism such that potable water may be access orretrieved directly from the reservoir. Still other types of waterretrieval systems or devices may be provided.

Support Structure and Tracking System

Turning now to FIG. 20, a dual axis tracking device 50 is shown. Thetracking device 50 may generally be configured to track the location ofan object in space, such as the sun, such that the device may direct apayload 51, such as solar panels, toward the object or at an anglerelative to the object. The tracking device 50 may track the location ofthe object over the course of a day or night, for example, as the objectmoves across the sky, such that the device may substantiallycontinuously direct its payload 51 at the appropriate angle.

FIG. 21 illustrates the tracking device 50 that may support and directthe payload 51. The tracking device 50 may have a base 210, an uprightportion 220, an arm portion 230, a spine portion 240, a first actuationassembly 250, and a second actuation assembly 260.

The upright portion 220 may generally support the weight of the trackingdevice 50 and any payload 51 the device may be carrying such as solarpanels. The upright portion 220 may support the tracking device 50 highenough off of the ground surface so as to allow for a full range ofmovement of the payload 51 by the first 250 and second 260 actuationassemblies. In some embodiments, the upright portion 220 may generallybe constructed of steel, aluminum, or other metals or metal alloys. Inother embodiments, the upright portion 220 may be constructed of one ormore plastics such as PVC, concrete, or any other suitable material. Theupright portion 220 may generally have any suitable length. The uprightportion 220 may have a rounded cross section as shown in FIG. 21, insome embodiments. In other embodiments, the upright portion 220 may haveany suitable cross sectional shape. The upright portion 220 may have anysuitable width or diameter. The upright portion 220 may connect with orto the ground surface via a base 210.

With continued reference to FIG. 21, the base 210 may provide lateralsupport for the upright portion 220. The base 210 may include a foot 212and one or more angular supports 214. In some embodiments, the trackingdevice 50 may be positioned on the ground surface. In other embodiments,the tracking device 50 may be positioned on a foundation, such as aconcrete foundation, or other surface. The foot 212 may be positionedbetween the upright portion 220 and ground surface, foundation, or othersurface. The foot 212 may have a width or diameter that is larger thanthat of the upright portion 220, so as to provide lateral support to theupright portion. In some embodiments, the foot 212 may be bolted orotherwise coupled to the ground, foundation, or other surface. In otherembodiments, the foot 212 may be positioned on the ground, foundation,or other surface without a coupling mechanism. Where the foot 212 is notbolted or otherwise coupled to the ground, foundation, or other surface,the foot may have a relatively large width or diameter, compared to theupright portion 220. However, where the foot 212 is bolted or otherwisecoupled to the ground, foundation, or other surface, the foot may have arelatively smaller width or diameter, in some embodiments. In otherembodiments, the foot 212 may have any suitable width or diameter. Asshown in FIG. 21, in some embodiments, the foot 212 may have a circularshape. In other embodiments, the foot 212 may have any suitable shape.The foot 212 may generally have any suitable thickness. One or moreangular supports 214 may strengthen the connection between the foot 212and the upright portion 220. The one or more angular supports 214 mayhave any suitable thickness. In some embodiments, the base 220 may beconstructed of steel, aluminum, or other metals or metal alloys. Inother embodiments, the base 220 may be constructed of one or moreplastics such as PVC, concrete, or any other suitable material.

With continued reference to FIG. 21, an arm portion 230 may couple tothe upright portion 220 to provide rotational support to the spineportion 240. The arm portion 230 may have a lateral member 232 and oneor more connector arms 234. In some embodiments, the lateral member 232may be positioned parallel to the spine portion 240. In someembodiments, the lateral member 232 may have a length that is longer,shorter, or the same as the length of the spine portion 240. Generally,the lateral member 232 may have a length sufficient to provide enoughsupport for the length of the spine portion 240, and the length of thelateral member may thus be proportion to the length of the spineportion. The one or more connector arms 234 may extend perpendicularfrom the lateral member 232 to connect to the spine portion 240. In someembodiments, as shown in FIG. 21, the arm portion 230 may have oneconnector arm 234 at each end of the lateral member 232. In otherembodiments, the arm portion 230 may have any suitable number ofconnector arms 234. Each connector arm 234 may couple to the spineportion 240 via a connector 236. The connector 236 may be or include aclamp, bolts, screws, or any suitable coupling mechanism. In someembodiments, the connector 236 may allow the spine portion 240 to rotateor twist. In some embodiments, the spine portion 240 may connectdirectly to the lateral member 232. For example, in some embodiments,the spine portion 240 may pass through an opening in the lateral member232. The lateral member 232 and connector arms 234 may have any suitablecross sectional shape, such as a rectangular shape for example. The armportion 230 may be constructed of steel, aluminum, or other metals ormetal alloys. In other embodiments, the arm portion 230 may beconstructed of one or more plastics such as PVC, or any other suitablematerial.

In some embodiments, the arm portion 230 may couple to the uprightportion 220 by a single axis support 238. The single axis support 238may comprise a pivoted connection and may provide for rotationalmovement about one or more axes, and in some cases two axes. In someembodiments, the single axis support 238 may allow for the arm portion230 to rotate about a first axis of rotation 252, which may beperpendicular to a longitudinal axis of the lateral member 232, and asecond axis of rotation 262 orthogonal to the first axis. The first andsecond axes of rotation 252, 262 may each pass through the connectionpoint between the arm portion 230 and the upright portion 220. In someembodiments, the spine portion 240 may connect directly to the uprightportion 230 via the single axis support 238.

With continued reference to FIG. 21, the spine portion 240 may providesupport and/or alignment for a payload 51 held by the tracking device50. For example, the device may carry one or more solar panels, in whichthe spine portion 240 may provide a base for supporting and/or aligningthe one or more solar panels. In this way, as the object is trackedacross the sky, the spine portion 240 may serve to align the payload 51with the object or with a point relative to the object. The spineportion 240 may be any suitable length and width or diameter so as toprovide sufficient support to the payload 51. The spine portion 240 mayhave any suitable cross sectional shape, such as a circular shape forexample. The spine portion 240 may be constructed of steel, aluminum, orother metals or metal alloys. In other embodiments, the spine portion240 may be constructed of one or more plastics such as PVC, or any othersuitable material.

With continued reference to FIG. 21, the tracking device 50 may have oneor more actuation assemblies that facilitate movement of the device.Generally, one or more actuation assemblies may facilitate movement ofthe arm portion 230, spine portion 240, and/or payload 51 with respectto the upright portion 220 and base 210. In some embodiments, thetracking device 50 may have a first actuation assembly 250 and a secondactuation assembly 260.

The first actuation assembly 250 may, in some embodiments, be positionedbetween the upright portion 220 and the arm portion 230. In otherembodiments, the first actuation assembly 250 may be positioned betweenthe spine portion 240 and the upright portion 220, or between the armportion 230 and spine portion 240, for example. Other positioningarrangements of the first actuation assembly 250 are contemplated aswell. The first actuation assembly 250 may facilitate movement of thearm portion 230, spine portion 240, and/or payload 51 with respect tothe upright portion 220 and base 210 about a horizontal axis. The firstactuation assembly 250 may couple to the upright portion 220 and armportion 230 using clamps, bolts, screws, or any suitable couplingmechanism. In some embodiments, the first actuation assembly 250 maycouple to the upright portion 220 and/or arm portion 230 with a pivoted,hinged, or other movable connection.

In some embodiments, the second actuation assembly 260 may be positionedbetween the arm portion 230 and the spine portion 240. In otherembodiments, the second actuation assembly 260 may be positioned betweenthe arm portion 230 and the upright portion 220, or between the spineportion 240 and the upright portion 220, for example. Other positioningarrangements of the second actuation assembly 260 is contemplated aswell. The second actuation assembly 260 may facilitate movement of thearm portion 230, spine portion 240, and/or payload 51 with respect tothe upright portion 220 and base 210 about the longitudinal axis of thespine. The second actuation assembly 260 may couple to the upright armportion 230 and spine portion 240 using clamps, bolts, screws, or anysuitable coupling mechanism. In some embodiments, the second actuationassembly 260 may couple to the arm portion 230 and/or spine portion 240with a pivoted, hinged, or other movable connection.

Using the first and second actuation assemblies 250, 260, the trackingdevice 50 may operate to position the spine portion 240 to direct apayload 51 toward or relative to a moving object, such as the sun. Inthis regard, the first actuation assembly 250 may provide for movementof the arm portion 230, spine portion 240, and/or payload 51 about afirst axis of rotation 252, as shown in FIG. 21. The first axis ofrotation 252 may be perpendicular to a longitudinal axis of the spineportion 240 and may be generally horizontal. Additionally, in someembodiments, the second actuation assembly 260 may provide for movementof the payload 51 about a second axis of rotation 262, which may be thelongitudinal axis of the spine. The two axes of rotation 252, 262 mayallow for the tracking device 50 to direct its payload 51 at a movingobject across the sky, in some embodiments, while the longitudinal axisof the spine portion 240 remains statically pointed in a direction. Thatis, where a third axis 222 aligns with the upright portion 220, thelongitudinal axis of the spine portion 240 may remain fixed with respectto rotation about the third axis. For example, where the longitudinalaxis of the spine portion 240 is directed North and South, the thirdaxis 222 and rotation about the third axis may be static such that thelongitudinal axis of the spine portion may continuously point North andSouth while movement about the first and second axes 252, 262 occurs.

FIG. 22A illustrates the first actuation assembly 250. The firstactuation assembly 250 may rotate the arm portion 230, spine portion240, and/or payload 51 about the first axis of rotation 252 with twopivot points 257, 258. The first pivot point 257 may be located wherethe first actuation assembly 250 couples to the arm portion 230. Thesecond pivot point 258 may be located where the arm portion 230 connectsto the upright portion 220 via the single axis support 238. The firstactuation assembly may comprise a linear actuator 254, such as a linearslide, and a motor 256 that drives the linear actuator. A slidingelement of the linear actuator 254 may couple to the upright portion 220with a fixed connection. In this way, as the motor 256 drives movementalong the linear actuator 254, the arm portion 230, spine portion 240,and/or payload 51 may pivot about the first and second pivot points 257,258, and be rotated about the first axis of rotation 252. It may beappreciated that the orientation of the linear actuator 254 may bereversed in some embodiments, such that the sliding element may coupleto the arm portion 230 and a pivot point may be located at theconnection between the first actuation assembly 250 and the uprightportion 220. The linear actuator 254 may have any suitable length andrange of motion in various embodiments. In some embodiments, the lengthmay depend on where along the arm portion 230 and upright portion 220the first actuation assembly 250 connects, and may further depend on therange of motion provided about the first axis of rotation 252.

The motor 256 may be a relatively inexpensive motor in some embodiments.For example, the motor 256 may be a low cost stepper motor. In otherembodiments, a DC motor or servo motor may be used. In otherembodiments, the motor 256 may be any suitable motor. The motor 256 mayrotate a gear screw or lead screw, for example, with each step. The gearscrew or lead screw may operate to drive the sliding element along thelinear actuator 254. In this way, the gear screw or lead screw maytranslate the rotational motion of the motor 256 into linear motion ofthe linear actuator 254. In some embodiments, the gear screw or leadscrew may couple to a gearbox, which may operate to drive the slidingelement along the linear actuator 254. The gearbox may provide foradditional torque to the linear actuator 254 in some embodiments. Agearbox may include one or more gears arranged in any suitableconfiguration. In some embodiments, a planetary gearbox may be used. Inother embodiments, any suitable gearbox may be used to assist withmoving the sliding element along the linear actuator 254. In someembodiments, any suitable gear reduction of the gearbox may be used toincrease the motor and gearbox output torque.

In some embodiments, the motor 256, linear actuator 254, and/or othercomponents may be configured for use in harsh conditions or otherwiseoutdoor use. For example, mechanical components may be configured tooperate without lubricating agents. In some embodiments, for example,the gear screw or lead screw may connect to the linear actuator 254 witha plastic bearing or other element that may function withoutlubrication, such as for example an IGUS DRYLIN bearing or other deviceto assist with movement. In some embodiments, the gear screw or leadscrew or one or more other components may be constructed of a materialsuch as that used in the IGUS DRYLIN devices. In other embodiments,similar materials or any suitable material may be used to provide foroperation without lubricating agents.

FIG. 22B illustrates the second actuation assembly 260. The secondactuation assembly 260 may twist the spine portion 240 so as to rotatethe payload 51 about the second axis of rotation 262. Like the firstactuation assembly 250, the second actuation assembly 260 may comprise alinear actuator 264 and a motor 266 that drives the linear actuator. Thesecond actuation assembly 260 may further comprise a torque arm 263 insome embodiments. The torque arm may connect the linear actuator to thespine portion 240. The second actuation assembly may connect to theupright portion 220 with a fixed connection, in some embodiments. Inthis way, the second actuation assembly 260 may rotate the spine portion240 and/or payload 51 about the second axis of rotation 262 with twopivot points 267, 268. The first pivot point 267 may be located wherethe second actuation assembly 260 couples to the torque arm 263. Thesecond pivot point 268 may be located where the torque arm 263 couplesto the spine portion 240. A sliding element of the linear actuator 264may couple to the upright portion 220 with a fixed connection. In thisway, as the motor 266 drives movement along the linear actuator 264, thespine portion 240 and/or payload 51 may pivot about the first and secondpivot points 267, 268, and be rotated about the second axis of rotation262. It may be appreciated that the orientation of the linear actuator264 may be reversed in some embodiments, such that the sliding elementmay couple to the spine portion 240 and a pivot point may be located atthe connection between the second actuation assembly 260 and the uprightportion 220. The linear actuator 264 may have any suitable length andrange of motion in various embodiments. In some embodiments, the lengthmay depend on where along the spine portion 240 and upright portion 220the second actuation assembly 260 connects, and may further depend onthe range of motion provided about the second axis of rotation 262.

Like motor 256 of the first actuation assembly 250, the motor 266 of thesecond actuation assembly 260 may be a relatively inexpensive motor insome embodiments. For example, the motor 266 may be a low cost steppermotor. In other embodiments, a DC motor or servo motor may be used. Inother embodiments, the motor 266 may be any suitable motor. The motor266 may rotate a gear screw or lead screw, for example, with each step.The gear screw or lead screw may operate to drive the sliding elementalong the linear actuator 264. In this way, gear screw or lead screw maytranslate the rotational motion of the motor 266 into linear motion ofthe linear actuator 264. As with motor 256, in some embodiments, thegear screw or lead screw may couple to a gearbox, which may operate todrive the sliding element along the linear actuator 264. The gearbox mayprovide for additional torque to the linear actuator 264 in someembodiments. A gearbox may include one or more gears arranged in anysuitable configuration. In some embodiments, a planetary gearbox may beused. In other embodiments, any suitable gearbox may be used to assistwith moving the sliding element along the linear actuator 264. In someembodiments, any suitable gear reduction of the gearbox may be used toincrease the motor and gearbox output torque.

In some embodiments, the motor 266, linear actuator 264, and/or othercomponents may be configured for use in harsh conditions or otherwiseoutdoor use. For example, mechanical components may be configured tooperate without lubricating agents. In some embodiments, for example,the gear screw or lead screw may connect to the linear actuator 264 witha plastic bearing or other element that may function withoutlubrication, such as for example an IGUS DRYLIN bearing or other deviceto assist with movement. In some embodiments, the gear screw or leadscrew or one or more other components may be constructed of a materialsuch as that used in the IGUS DRYLIN devices. In other embodiments,similar materials or any suitable material may be used to provide foroperation without lubricating agents.

In some embodiments, the tracking device 50 may be connected to a powersource. The power source may operate the motors 256, 266 of the firstand second actuation assemblies 250, 260. The power source may consistof AC and/or DC power, such as battery power, or other power sources insome embodiments. The power source may additionally power a controlmodule in some embodiments.

In some embodiments, the tracking device 50 may be connected to acontrol module. The control module may consist of hardware and/orsoftware components. The control module may be connected to the motors256, 266 in some embodiments. In some embodiments, the control modulemay determine an approximate position of an object moving across thesky, such as the sun. The control module may include a GPS system insome embodiment, which may include hardware and/or software, such thatthe control module can determine where on the earth it is located andthe local time of day and date. The control module may use hardwareand/or software to determine the position of an object in space, such asthe sun, from the GPS information. For example, the control module maybe configured to determine the azimuth and altitude of the sun from thelocation of the tracking device 50, as discussed more fully below. Thecontrol module may additionally or alternatively be configured to sendinstructions to the motors 256, 266 to drive the first and secondactuation assemblies 250, 260. For example, the control module mayinstruct the motors 256, 266 to position the payload 51 to be directedtoward or relative to the moving object, such as the sun. In someembodiments, the control module may include any or all of the elementsshown in FIG. 28. It should be understood that the particular elementsshown in FIG. 28 are illustrated as examples. In other embodiments, thecontrol module may include elements similar or related to those shown inFIG. 28 or other elements not depicted in FIG. 28.

In use, the tracking device may operate to track the location of anobject and direct the payload toward or relative to that object. Forexample, in some embodiments, the tracking device may use GPSinformation to determine the location of the device, and from thatinformation, the location of the sun. For example, the tracking devicemay use such GPS information as a triangulated location, time, and dateto determine an altitude and azimuth of an object in space, such as thesun. The tracking device may additionally or alternatively operate todirect its payload, such as one or more solar panels, toward thedetermined location of the object in space by way of the first andsecond actuation assemblies. In other embodiments, the tracking devicemay operate to direct its payload toward a location or object relativeto the determined location of the object ins pace by way of the firstand second actuation assemblies. Various algorithms may be used todetermine an altitude and azimuth based on GPS information. Once theazimuth and altitude are known, the location can be converted into afirst motion path, performed by the first actuation assembly, and asecond motion path, performed by the second actuation assembly. FIG. 23illustrates a method 400 that the tracking device may perform in someembodiments. The method may include a calibration step (410), receivingGPS information (420), determining location of the object in space, suchas the sun (430), determining positioning of the device (440), andpositioning the device (450).

In some embodiments, the device may perform a calibration step (410). Insome embodiments, the calibration step may be performed automatically.For example, the calibration step may be performed automatically whenthe tracking device initially powers on at a location. In otherembodiments, the calibration may be performed based on some user input.In some embodiments, the calibration step may be performed partially orentirely manually. The calibration step may include determining one ormore assumptions. That is, in some embodiments, the tracking device mayoperate, at least in part, based on one or more assumptions. Forexample, in some embodiments, an assumption may be that the longitudinalaxis of the spine portion 240 is directed North at one end and directedSouth at an opposing end. Such assumptions may provide for more accuratepositioning of the spine portion and/or payload in some embodiments.Based on these assumptions, the tracking device may be used to track thelocation of an object from any location on the earth's surface. Acorrect assumption (such as a first end of the longitudinal axis of thespinal portion is directed North in the Northern Hemisphere) may allowthe tracking device to accurately track the location of a moving objectand direct its payload accordingly. In this way, it may be appreciatedthat the tracking device may be able to track the location of an objectfrom any location on the earth's surface merely by changing theassumption(s). For example, an assumption in the Northern Hemisphere maybe that a first end of the spinal portion is directed North. Foroperation in the Southern Hemisphere, the assumption may be changed toreflect that the first end of the spinal portion is directed South.

The calibration step (410) may additionally or alternatively includehoming the first and second actuation assemblies. Homing an actuationassembly may include operating the motor, such as a stepper motor, toone end of travel until the motor reaches a limit switch, such as anelectromechanical limit switch, defining a limit of travel for thelinear actuator. The tracking device may register the point of the limitswitch as a zero point of motion of the actuation assembly. Positioningof the device may then be determined based on the zero points of motionfor each actuation assembly. This may allow the control module to moreaccurately determine the relationship between the motor operation andthe positioning of the spine portion and/or payload. In someembodiments, once the calibration step is completed, the tracking devicemay be able to power off and on without the need for recalibration. Insome embodiments, the tracking device may know its position each time itturns on after calibration because the actuation assemblies may have azero back drive. That is, in some embodiments, each actuation assemblymay have sufficient forces preventing the linear actuator and/or drivescrew or lead screw from moving without the motor drive enabled. In someembodiments, where for example the motors are stepper motors, the motorsmay additionally or alternatively help to prevent the linear actuatorsand/or drive screws or lead screws from moving during shut off. Further,in some embodiments, the gearbox may additionally or alternatively helpto prevent the linear actuators and/or drive screws or lead screws frommoving during shut off.

In some embodiments, a device such as a rotary encoder or linearabsolute encoder may be used to determine a position of the linearactuator with respect to the motor operation. In some embodiments, alinear absolute encoder or other similar device may provide a locationof the linear actuator to the tracking device, such that the trackingdevice may know the position of the linear actuator with respect to themotor. In this way, the linear absolute encoder may, at least in part,reduce or obviate the need for homing an actuation assembly. Forexample, the linear absolute encoder may provide a position of a linearactuator when the tracking device powers on, when the device begins atracking routine, at the request of the tracking device or a user,and/or at any other suitable time. Each actuation assembly may operateusing a linear absolute encoder in some embodiments. The use of one ormore linear absolute encoders or similar device may allow the trackingdevice to correct for any intentional or unintentional movement of theactuation assemblies that may occur during power shut offs or betweentracking routines, for example.

As shown in FIG. 23, the tracking device may receive GPS information(420). In some embodiments, the GPS information may be received at thetracking device from a source. For example, the GPS information may besent to the tracking device over a wired or wireless network. In otherembodiments, the device may have GPS hardware and/or software, asdiscussed above, and may determine the GPS information internally using,for example, data transmitted by a GPS satellite constellation andreceived by onboard GPS antenna and hardware. GPS information mayinclude location information such as triangulated coordinates, date, andtime, each related to the tracking device's current location. Using theGPS information, the tracking device may determine its exact orapproximate location on the surface of the earth.

Based on the received GPS information, the tracking device may determinethe location of a moving object in space, such as the sun (430). Forexample, the tracking device may determine an azimuth and altitude of anobject in relation to the device's position. Where the moving object isthe sun, the azimuth and altitude may be calculated from the GPSinformation based on a Solar Position Algorithm, provided by the U.S.Department of Energy, for example. In other embodiments, othercalculations or methods may be used to determine the azimuth andaltitude of an object or other location information. FIG. 24Agraphically illustrates the location of an azimuth 510 and altitude 520in relation to a location 530 of an object in space, such as the sun,and the location 540 of the tracking device 50. Both locations 530, 540are shown in relation to North, South, East, and West directions and inrelation to a vertical Z axis. The azimuth 510 and altitude 520 combineto provide the location vector 530 of the sun or other object. FIG. 24Bgraphically illustrates the angle of the first motion path M1, relatedto the first actuation assembly 250, and the angle of the second motionpath M2, related to the second actuation assembly 260. FIG. 25graphically illustrates the variables used to calculate the angles ofthe first motion path M1 and the second motion path M2, according tosome embodiments. In some embodiments, the angles of the motion pathsM1, M2 may be calculated by the following:

A=180−Azimuth

a=|tan(A)|

R=√{square root over (1² +a ²)}

e=R tan(Altitude)

M=tan⁻¹ e/a

M1=tan⁻¹(e)

M2=

if A>1801|M|180−M

In other embodiments, other equations, calculations, or other methodsmay be used to determine the angles of the motion paths M1, M2. Forexample, in some embodiments, the calculation of M2 (i.e., the day axisangle) may be adjusted to accommodate the reference angle established byM1 (i.e., the season axis angle). In some embodiments, this may beperformed by transforming the M2 back to an offset cylindricalcoordinate system based on M1. This transform would allow for higheraccuracy at higher latitudes. Accordingly, by using a trigonometrictransform to transform M2 back to an offset cylindrical coordinatesystem based on M1 and then calculating the M2 angle, the effect on M2results in higher accuracy across a range of latitudes and seasons.

With continued reference to FIG. 23, from the angles of the motion pathsM1, M2, the tracking device may determine where to direct the spineportion and/or payload, such that they are directed toward the object(440). For example, in some embodiments, the tracking device maydetermine a linear distance for each actuation assembly 250, 260 todirect the spine portion and/or payload toward the object. FIG. 26Agraphically illustrates the variables used to calculate the first linearmotion b3, according to some embodiments. In some embodiments, the firstlinear motion b3 may be calculated by the following:

b2=Length Torque Arm

b1—Length Pivot Support

b4=M1−(b6−b4)

b3=√{square root over ((b1² +b2²−2*b1*b2))}

b3=First Linear Motion

FIG. 26B illustrates the locations of the torque arm length b2 and thepivot support length b1 in relation to the first actuation assembly 250.In other embodiments, the first linear motion b3 may be determined usingother equations, calculations, or method.

FIG. 27A. Graphically illustrates the variables used to calculate thesecond linear motion c2, according to some embodiments. In someembodiments, the second linear motion c2 may be calculated by thefollowing:

c1=Length Torque Arm

c3=Length Pivot Support

c5=M1+90

c2=√{square root over ((c2+c3²−2*c1*c3))}

c2=Second Linear Motion

FIG. 27B illustrates the locations of the torque arm length c1 and thepivot support length c3 in relation to the second actuation assembly260. In other embodiments, the second linear motion c2 may be determinedusing other equations, calculations, or methods. It may be appreciatedthat in other embodiments, the tracking device 50 may determine adirection for the payload by means other than linear motion. Forexample, the tracking device may angle the spine portion and/or payloadfrom the ground surface, based on the first and second motion paths M1,M2.

It may be appreciated that the tracking device may be configured todirect its payload at an angle relative to the object moving across thesky. For example, in some embodiments, the payload may be a heliostat orsimilar device having a mirror or other reflective surface. The mirroror other reflective surface may be directed at an angle relative to thesun's location, such that it may reflect the sunlight toward anotherpoint which may be a stationary point. In such embodiments, the firstand second linear motions may be calculated differently than above. Thatis, after determining the sun's azimuth and altitude, the trackingdevice may determine the first and second linear motions based on thelocation of the sun in the sky and an angle between the sun's locationand the location of the point onto which the sunlight is to bereflected. Generally, the tracking device may be configured to directits payload at any angle relative to the moving object's location. Inthis way, it may be appreciated that the tracking device may receiveinstructions to direct the payload toward generally any vector which mayor may not depend on the location of the object being tracked. Theinstructions may be received locally or remotely over a wired orwireless network. It some embodiments, the positioning of the trackingdevice may be fully controlled remotely.

With the first and second linear motions b3, c2, the tracking device mayinstruct the motors to position the actuation assemblies so as to directthe payload toward the moving object or toward a different position(450). Where the motors are stepper motors, for example, the trackingdevice may determine a number of steps to operate on each motor, so asrotate the payload about the first and second axes of rotation 252, 262to a desired position.

In some embodiments, the tracking device may repeat steps 420 through450 intermittently or continuously. For example, in some embodiments,the tracking device may operate continuously to determine the locationof the object in space and continuously update the device's positioning.In other embodiments, the tracking device may determine the object'slocation and reposition the device at intervals. For example, thetracking device may recalculate location and position every hour in someembodiments. In other embodiments, the tracking device may recalculatelocation and position every 15-45 minutes. In still other embodiments,the tracking device may recalculate location and position every 1-15minutes in some embodiments. Particularly, the tracking device mayrecalculate location and position every 2-5 minutes in some embodiments.In this way, the device may take advantage of an object's relativelyslow movement across the sky during the course of a day or night. Forexample, the location of the sun, may not move very far relative to thedevice over the course of a 2-5 minute interval. In other embodiments,the system may update location and position at different intervals. Inthis way, for example where the device is directing a payload of solarpanels at the sun, the device may be able to recalculate intermittentlywithout substantial solar collection efficiency loss. In addition, theability to operate intermittently may allow the device to operate withrelatively low power consumption. In some embodiments, a low power timermay operate to power the device on at intervals and then the device maypower off after adjusting. The process of determining the sun's locationand repositioning the device may be a relatively fast process, such thatthe device does not require much power when it powers on at intervals.For example, in some embodiments, over a twelve hour period of trackingthe sun across the sky, the device may be powered off approximately 98%of the time.

In some embodiments, the tracking device may reference a calibrationlookup table automatically or manually for purposes of error correction.A calibration lookup table may include a plurality of angles or motionpaths relating to directing the payload and corresponding correctionangles or correction paths, for example. That is, the lookup table mayinclude error corrections to be performed by the first and/or secondactuation assemblies for various calculated motion paths, angles, orobject locations. The error corrections of the lookup table may allowthe device to correct for various sources of error inherent in orotherwise found in the device. For example, error may be introduced bysmall inconsistencies in machining, motion of the linear actuator inresponse to each motor step, small calculation inaccuracies, which mayrelate to index of refraction of the atmosphere or other atmosphericconditions for example, and/or other sources of error. The lookup tablemay include a plurality of calculated positions or other calculations asperformed by the tracking device, along with corresponding errorcorrections. In some embodiments, the lookup table may be determinedbased on actual device calculations performed over time, such as overthe course of a day, month, or year, for example. The correspondingerror corrections may be determined automatically or manually in someembodiments. Likewise, the lookup table may be populated automaticallyor manually. In some embodiments, the error corrections may bedetermined and/or populated in the lookup table using an applicationsuch as a mobile phone application. In some embodiments, errorcorrections may be determined for a limited number of location orposition calculations, or for a period of time such as a day, forexample, and additional error corrections may be extrapolated. In someembodiments, such calculations and extrapolations may be performedremotely using an application, such as a mobile phone or computerapplication. In some embodiments, an error correction lookup table or aportion thereof may be directly sent or supplied to the tracking device.In some embodiments, the tracking device may be automatically ormanually directed to reference the lookup table periodically, such asafter each location and position recalculation. In some embodiments,where a required error correction is not found on the lookup table for aparticular calculated location, direction, or motion, bicubicinterpolation or another interpolation method may be used to interpolatethe needed error correction between two similar correction errors foundin the lookup table.

FIG. 29 illustrates a method 1000 for populating a lookup table witherror corrections. As shown, the tracking device may receive GPSinformation (1010), determine a location of the moving object (1020),and determine a linear motion needed to direct the payload (1030), asdescribed above with respect to method 400. Additionally, in someembodiments, an error correction for the linear motion may be determined(1040). The error correction may be determined automatically ormanually, such as through the use of a mobile phone application or otherapplication, locally or remotely. A lookup table may be populated withthe determined error correction (1050). In some embodiments, steps 1020through 1050 may be repeated until a plurality of data points arepopulated in the lookup table. In some embodiments, additional errorcorrections may be extrapolated to expand the lookup table (1060).Various extrapolation methods may be used in different embodiments.

FIG. 30 illustrates a method 1100 that the tracking device may performin some embodiments in order to position the payload with considerationof the lookup table error corrections. As shown, the method 1300 mayinclude a calibration step (1110), receiving GPS information (1120),determining a location of a moving object (1130), and determining alinear motion needed to direct the payload (1140), as described abovewith respect to method 400. Additionally, the method 1100 may includereferencing an error correction lookup table (1150). The tracking devicemay be directed automatically or manually to reference the lookup table.Additionally, where needed in some embodiments, for example if theparticular location or positioning does not fall within the errorcorrection lookup table, the tracking device may interpolate an errorcorrection (1160). Generally, any suitable interpolation method may beused, and in some embodiments, bicubic interpolation may be employed.Taking into account the error correction, the tracking device may directits payload (1170) using one or more actuation assemblies. In someembodiments, steps 1120 through 1170 may be repeated intermittently orcontinuously, as described above in order to recalculate location of thetracked object and positioning of the tracking device.

It may be appreciated that the first and second actuation assemblies mayrelate generally to a season axis and a day axis in some embodiments.That is, the first actuation assembly, first axis of rotation, and firstlinear motion may be related to a seasonal position of the object beingtracked. For example where the object being tracked is the sun, thesun's location may depend in part on the time of year. The positioningof the first actuation assembly may correlate with the sun's locationduring a particular time of year in some embodiments. Similarly, it maybe appreciated that the second actuation assembly, second axis ofrotation, and second linear motion may be related to a daily position ofthe object being tracked. For example where the object being tracked isthe sun, the sun's location may depend in part on the time of day. Thepositioning of the second actuation assembly may correlate with thesun's location at a particular time of day in some embodiments. It mayadditionally be understood that while the first and second actuationassemblies may correlate generally with time of year and time of day,both actuation assemblies and axes of rotation may be used to direct thepayload at any time of day or year. For example, although the firstactuation assembly may generally correspond with seasonal location, thefirst actuation assembly may additionally rotate the payload about thefirst axis of rotation to track the object based on the time of day.That is, both actuation assemblies may be used to track the object'smovement across the sky during the course of a day, for example.

In various embodiments, a tracking device of the present disclosure maybe mounted to or generally located on a ground surface, a platformsurface, or a tower surface or other structure, such as a cell phone orother communication tower or a solar power tower. For example, where thetracking device is mounted on a cell phone or other communication tower,the tracking device may track the location of a satellite and/or maydirect its payload toward the satellite. In other embodiments, thetracking device may be located on a solar power tower, where the devicemay track the location of the sun and/or may direct its payload, such asmirror or other reflective surface, at an angle relative to the sun suchthat sunlight may be reflected toward a power collector or other deviceon the power tower. In such tower embodiments, the tracking device maybe controlled or directed automatically and/or remotely, in someembodiments.

In some embodiments, the tracking device may operate, at least in part,over a wired or wireless network. A wireless connection may be, forexample, an internet, Wi-Fi, Bluetooth, or other wireless connection. Insome embodiments, the device may have a digital radio such as a Zigbeeradio, which may allow the tracking device to communicate with one ormore additional tracking devices or other communication devices over awireless network. In this way, one or more tracking devices may beconfigured to share information, such as GPS information, tracking andpositioning information, power consumption information, efficiencyinformation, and/or other information over a wireless network. In someembodiments, the network and communication link may be maintained duringpower shut offs.

In some embodiments, the tracking device may receive an instruction toturn away from the object being tracked across the sky or otherwise awayfrom its point of direction. For example, where the tracking device istracking the sun to collect solar light or radiation, if the trackingdevice reaches some input or output limit or it is otherwise determinedthat solar light or radiation need not be collected for a period oftime, the tracking device may be configured to receive an instruction todirect the payload away from the sun. Such an instruction may bereceived locally or remotely over a wired or wireless connection. Forexample, the instruction may be received from a device having a Zigbeeradio. In some embodiments, the instruction may be receivedautomatically when a sensor, for example, determines that the trackingdevice should stop collecting solar light or radiation. In otherembodiments, the instruction may be input into the tracking devicemanually or may be received based on some user input.

In some embodiments, one tracking device may operate as a node tocontrol one or more additional tracking devices. For example, onetracking device may aggregate the information received from multipletracking devices. The single tracking device may direct and controlpositioning of the additional tracking devices, in some embodiments.

In some embodiments, a software application may allow a computing deviceto communicate with one or more tracking devices. A computing device maybe a desktop or laptop computer, tablet, or mobile phone, for example.The software application may be used to communicate with one or moretracking devices over a wired or wireless network. The softwareapplication, such as a mobile device application for example, may allowa user to calibrate the tracking device locally or remotely. Theapplication may further allow a user to collect data and/or provide userinputs locally or remotely.

In the foregoing description, a tracking device has been described. Thetracking device may be configured to track an object in space, such asthe sun, as the object moves across the sky. The tracking device mayfurther be configured to direct a payload toward the object in space ortoward an angle relative to the object in space. The tracking device maycontinuously or intermittently determine the location of the movingobject, and adjust the position of the payload accordingly. The trackingdevice may calculate the position of the moving object based on GPSinformation, such as triangulated coordinates of the tracking device,date, and time. Generally, the tracking device may be capable oftracking an object such as the sun from anywhere on the earth's surface.The tracking device may employ one or more actuation assemblies toposition the payload toward or relative to the moving object. The one ormore actuation assemblies may operate through linear motion, in someembodiments. Moreover, the tracking device may operate with relativelylow power consumption. The tracking device may communicate with one ormore additional tracking devices or other communication devices over awired or wireless network.

System Operation

In use, the system may be set up by providing the several elements andarranging them so as to be exposed to sunlight and such that water maybe supplied. In some embodiments, the support structure of the systemmay be arranged on a relatively flat surface in a manner such that thespine of the support structure is arranged along a North/South axis onthe surface of the earth. Where the device is positioned north of theequator, the upper end of the fluid control system (i.e., the end havingthe control valve and the pressure relief device) may be arranged on thenorth end of the system. In contrast, where the device is positionedsouth of the equator, the upper end of the fluid control system may bearranged on the south end of the system. The control electronics may beturned on allowing the GPS system in the controls to identify thelocation of the device on the surface of the earth and also identify thedate and time. With this information, the control electronics may beable to identify the position of the sun relative to the device. Thesystem may then automatically actuate the seasonal actuation assemblyand the daily actuation assembly to tip the solar collector to aposition facing the sun.

In addition, portions of the fluid control system may be arranged. Forexample, the collection reservoir may be arranged in a position tocollect water and may be positioned at an elevated position relative tothe remaining parts of the system. In some embodiments, the collectionreservoir may be placed on a hill or on a stand, tower, or other devicefor elevating the collection reservoir. The feed line may be secured tothe collection reservoir and the preheat heat exchanger. In addition,the effluent line may be connected to the preheat heat exchanger and tothe treated fluid collection reservoir. The treated fluid collectionreservoir may be arranged at a non-elevated position relative to thesystem such that the collection reservoir may receive water from thesystem based on a gravity flow, for example. In some embodiments, thereturn line, the preheat heat exchanger, the effluent line, and thetreated fluid collection tank may be sanitized so as to avoid asituation where treated fluid is run through a contaminated line ordevice or placed into a contaminated container.

Water from the elevated collection reservoir may be allowed to flow intothe system. The degassing valve may allow air or gas in the system to bereleased as water or fluid flows into the system. In some embodiments,to avoid overheating and damage to the system, water may be provided tothe system prior to having the system face the sun. For example, werethe system to heat up prior to allowing water or fluid to enter, thewater may boil as it enters creating high pressures that may damage thesystem.

With the system primed, gases removed, and having the system facing thesun, the system may begin heating the water or fluid in the elongatedflow element of the fluid heating portion. As shown in FIG. 31, thetemperature of the water or fluid in the elongated flow element maygenerally increase substantially uniformly until the fluid in thecontrol valve assembly reaches a thermal temperature causing one or moreportions of the valve to open. As the valve opens, fluid or water in theelongated flow element may begin to flow. Accordingly, a temperaturegradient across the elongated flow element may begin to develop becausecool or slightly preheated water may enter the inlet end of theelongated flow element and it may continue to get warmer as the waterflows through the elongated flow element and is continually exposed toadditional heat. As shown in FIG. 31, the system may reach a state ofquasi equilibrium as the valve opens and closes periodically and beginsto allow water or fluid to pulse through the elongated flow element. Thecontrol valve assembly may be particularly designed, constructed andcalibrated to ensure that the water or fluid in the elongated flowelement is exposed to sufficient temperatures for sufficient lengths oftime such that all relevant pathogens are inactivated. As the controlvalve opens and closes, pasteurized water may flow through the controlvalve assembly and into the return line. The water or fluid may thenflow through the return line and into the preheat heat exchanger. As thepasteurized water flow through the preheat heat exchanger, heat fromthis pasteurized water may be transferred to the incoming water from thefeed line allowing this water to increase in temperature before enteringthe elongated flow element. The pasteurized water may then pass into theeffluent line and into the treated water collection reservoir where itmay be available for use.

As mentioned, the control valve assembly may be particularly designed,constructed, and calibrated to ensure that the water or fluid passingthrough the control valve assembly is fully pasteurized. That is, theuse of thermally activated valves inherently results in a pulsing typeflow, where, when the valve opens water flows, which allows cooler waterto reach the valve causing the valve to close. When the valve is closed,the standing water near the valve then increases in temperature due toremaining exposed to the heat source. As such, the valve then opens onceagain. During the process of water flowing through the valve and thetime it takes for the valve to react to the cooler temperatures, a riskexists that non-pasteurized water may escape through the valve unlessthe valve is properly designed. Accordingly, the valve may be designedand calibrated to make sure that the temperatures at which it opens andcloses are such that no unpasteurized water escapes. At the same time,substantially continuous flow or quasi continuous pulsing flow of fluidmay be desired so as to efficiently utilize the heat source andefficiently create pasteurized water.

Pathogen Inactivation

In order to discuss how to analyze pathogen inactivation for pulsingflow fluid, an initial discussion of pathogen inactivation may behelpful. Two related methods of pathogen inactivation may be provided.In some embodiments, a decimal reduction time may be used which may bethe time required for 1-log reduction in pathogens. Mathematically, thismay be expressed as:

$\begin{matrix}{{\log \; \left( \frac{N_{t}}{N_{0}} \right)} = \frac{- t}{D}} & {{Eq}.\mspace{14mu} 1}\end{matrix}$

In this equation, No may be initial pathogen population and N_(t) may bethe population at a later time t. The value of D (i.e., the decimalreduction time) may depend on the exposure temperature and the type ofpathogen. The value of D may decrease relatively quickly as temperatureincreases. Values of D at other temperatures can be found from:

$\begin{matrix}{{\log \; \left( \frac{D}{D_{r}} \right)} = \frac{- \left( {T = T_{r}} \right)}{z}} & {{Eq}.\mspace{14mu} 2}\end{matrix}$

where the term D_(r) is the decimal reduction time known at somereference temperature T_(r). On the other hand, D is the desiredreduction time at a different temperature T. The symbol z has units of °C. The information presented in the Equations 1 and 2 may be usefulparticularly for isothermal exposures. However, it is often moreconvenient to calculate instantaneous rates of pathogen destructionthrough a first-order rate model which can be expressed as

$\begin{matrix}{\frac{N}{t} = {- {kN}}} & {{Eq}.\mspace{14mu} 3}\end{matrix}$

For isothermal exposures, Equation 3 can be integrated in time, to give

$\begin{matrix}{{\ln \; \left( \frac{N_{t}}{N_{0}} \right)} = {- {kt}}} & {{Eq}.\mspace{14mu} 4}\end{matrix}$

and a comparison of Equations (1) and (4) may allow a relationshipbetween k and D such as:

$\begin{matrix}{k = \frac{2.303}{D}} & {{Eq}.\mspace{14mu} 5}\end{matrix}$

For time-varying situations, such as the fluid system in the presentapplication, the integration of Equation (3) may be carried outnumerically so that

$\begin{matrix}{\frac{N}{t} = {\frac{\left( {N_{t + {\Delta \; t}} - N_{t}} \right)}{\Delta \; t} = {{- {kN}_{t}} = {\frac{2.303}{D_{r}} \cdot 10^{\frac{({T - T_{r}})}{z}} \cdot N_{t}}}}} & {{Eq}.\mspace{14mu} 6}\end{matrix}$

which will be solved using a forward-stepping integration scheme. Withvalues of D (at a reference temperature) and z for various pathogenssolutions may be determined. Alternatively, values of D at two separatetemperatures can be used.

This microbiologic model may be applied to described fluid heatingsystem. That is, with knowledge of the parameters of the systemdescribed, temperatures of the flowing fluid in the elongated flowelement may be calculated and analysis of the related effect on pathogeninactivation may be determined. For purposes of the analysis, severaltemperatures at several locations within the system may be identified.For example, T_(in) may be the incoming temperature of the fluid cominginto the heat exchanger (i.e., the fluid temperature in the feed line).Additional temperatures T₁-T₆ may be calculated along the length of theelongated flow element. That is, as shown in FIG. 32, T1 may be thetemperature as the fluid enters the elongated flow element (i.e., thetemperature after passing through the preheat heat exchanger).Temperatures T₂, T₃, T₄, T₅ and T₆ may be temperatures calculated atequal distances along the length of the elongated flow element with T₆being the exit temperature and/or the activation temperature for thecontrol valve assembly. The volumes of fluid between each of thesetemperature locations may constitute control volumes where thetemperature rise across each control volume may be determined from anenergy balance as described below. In addition to the above-mentionedtemperatures, an additional temperature T₇ where the return tube entersthe preheat heat exchanger may be calculated. In some embodiments,adequate insulation of the return tube may be assumed such that T₆ isequal to T₇. T_(out) may be the temperature of the fluid as it exits thepreheat heat exchanger and heads toward the treated water collectionreservoir.

With focus on the solar collector or other heat source, the time wiseevolution of temperature may be based on an unsteady energy balance asfollows:

$\begin{matrix}{{\Delta \; q} = {{\overset{.}{m} \cdot {c_{p,{fluid}}\left( {T_{n + 1} - T_{n}} \right)}} + {\left\lbrack {\left( {m \cdot c_{p}} \right)_{fluid} + \left( {m \cdot c_{p}} \right)_{pipe}} \right\rbrack_{n}\frac{T_{n}}{t}}}} & {{Eq}.\mspace{14mu} 7}\end{matrix}$

where the symbol Δ may reflect that the energy balance is performed overa small region (i.e., one of the control volumes along the elongatedflow element). The symbol in may be the mass flow rate and c_(p) may bethe specific heat of either the fluid or the pipe wall as respectivelycalled for. The symbols T_(n) and T_(n+1) represent the temperatures atthe inlet and the exit of a particular control volume. The first term onthe right hand side may be the heat that is used raising the temperatureof the flowing fluid. The second term on the right may be the energyused to raise the temperature of the pipe and the fluid within the pipe.It may be assumed that the fluid and the pipe in any control volume areat equal temperatures; axial conduction may be neglected.

The net influx of heat, Δq, may include energy gain by thermal radiationas well as energy lost by both convective and infrared heat loss. Forexample, Δq, may be found from:

Δq=(Δq)_(solar)−(Δq)_(convection)−(Δq)_(IR)  Eq. 8

where

(Δq)_(solar) =I _(solar) ·ΔA _(collector) ·F  Eq. 9

is the solar influx of heat. The symbol I_(solar) may be the insolationflux at the ground, ΔA_(collector) is the parabolic solar collectionarea for the control volume under consideration.

The term F represents losses from incomplete reflection at the mirrorsurface or absorption at the pipe which resides along the focal axis andany imperfect alignment of the pipe along the focal line. This number isexpected to be very close to 1 for high-quality parabolic systems.

The convective losses may be calculated from

$\begin{matrix}{\left( {\Delta \; q} \right)_{convection} = {\overset{\_}{h}\Delta \; {A_{surf}\left( {\frac{\left( {T_{n + 1} + T_{n}} \right)}{2} - T_{amb}} \right)}}} & {{Eq}.\mspace{14mu} 10}\end{matrix}$

where the symbol h is the average convective coefficient on the controlvolume under consideration. This value depends on both local wind aswell as the temperature of the pipe if buoyant flow makes an impact.Correlations are available for convective calculations in manyresources. Calculations show that final temperatures are nearlyindependent of the convective coefficient so long as a reasonable valueis assigned.

In a similar manner, the heat loss by infrared radiation may becalculated from

$\begin{matrix}{\left( {\Delta \; q} \right)_{IR} = {{\varepsilon\sigma\Delta}\; {A_{surf}\left( \left( \frac{\left( {T_{n + 1} + T_{n}} \right)}{2} \right)^{4} \right)}}} & {{Eq}.\mspace{14mu} 11}\end{matrix}$

where ε and σ are the emissivity and Stefan-Botzmann constant,respectively. The control volume temperature in Equation 11 may beexpressed in absolute units. In Equation 11, no account has been madefor incoming infrared radiation from above the pipe. However, thiscomponent is expected to be much smaller than other components.

For high-performance solar concentrators, a surrounding tube or housingmay be used to provide thermal insulation. The presence of such a tubemay be incorporated into the present analysis through the inclusion of aseries of thermal resistance which may be applied to the heat loss. Onthe other hand, for low-cost solar pasteurization systems designed forrugged environments and the developing world, such high-cost insulatingtubes may be difficult to justify.

When terms from Equations 8-11 are evaluated at timestep i, temperatureat the following time i+1 may be found by numerically integratingEquation 7 as

$\begin{matrix}{{T_{n + 1}^{i + 1} = {T_{n + 1}^{i} + {\Delta \; {t\left\lbrack \frac{{\Delta \; q} - {\overset{.}{m} \cdot {c_{p,{fluid}}\left( {T_{n + 1} - T_{n}} \right)}}}{\left\lbrack {\left( {m \cdot c_{p}} \right)_{fluid} + \left( {m \cdot c_{p}} \right)_{pipe}} \right\rbrack_{n}} \right\rbrack}^{i}}}},{n = 1},2,\ldots} & {{Eq}.\mspace{14mu} 12}\end{matrix}$

In FIG. X, temperatures T7=T6. The final unknown is the temperature T1.This value may be determined using an effectiveness-NTU heat exchangeranalysis method which gives

T ₁ ^(i+1) =T _(in) +e(T ₇ −T _(in))^(i)  Eq. 13

where e is the heat exchanger effectiveness.

If a thermal valve is used to control flow when temperatures are below athreshold, then {dot over (m)}=0 when the valve is closed (i.e., thewater is not flowing). The valve remains closed when the temperature atthe valve (typically at the exit of the elongated flow element) is lessthan valve operation temperature. If the valve has opened, then the massflow rate may be determined by considering a fluid mechanical-energyequation,

$\begin{matrix}{{\rho \; {gh}_{tank}} = {\frac{\rho \; V^{2}}{2} + {f\frac{L}{d}\frac{\rho \; V^{2}}{2}} + {\Delta \; P_{minor}}}} & {{Eq}.\mspace{14mu} 14}\end{matrix}$

Here, ΔP_(minor) are the contributions to pressure loss other thanfriction. Equation 14 allows calculation of the fluid velocity withinthe pipe, V from

$\begin{matrix}{V = \sqrt{\frac{2{gh}}{\left( {{f\frac{L}{d}} + K_{inlet} + K_{valve}} \right)}}} & {{Eq}.\mspace{14mu} 15}\end{matrix}$

Here, the K_(inlet) and K_(valve) are minor loss coefficients at thepipe inlet and at the valve. If there are other minor losses within thesystem, their loss coefficients may be added in the denominator. Thesymbol f is the friction factor which may be determined based on theflowrate and Reynolds number at the prior time step. With the fluidvelocity, and consequently mass flow rate now known, the entirecalculation algorithm can be articulated.

At time step t=0, all temperatures may be initialized to a startingvalue equal to the water temperature in the storage container. At latertime steps,

Step 1: T_(in)—temperature of water in the storage tankStep 2: T₁ is solved from Equation 13 to account for preheat at the heatexchangerStep 3: T₂, T₃, . . . T₆ may be found from Equation 12Step 4: T₇=T₆Step 5: Compare T₆ to a valve operation temperature, updated mass flowrate Equation 15, repeat step 1.

Results of the temperature calculation can be seen in FIG. 31 for aparticular set of input parameters. In the image, five of thetemperatures are shown which represents temperatures along the elongatedflow element. The settings for the calculation are shown in FIG. 33. Thekinematic viscosity of water may be calculated at each time step by thefollowing interpolating function

v(T)=1.10×10⁻¹⁰ ·T ²−2.17×10⁻⁸ ·T+1.37×10⁻⁶ (m²/s)  Eq. 16

with temperatures in degrees C. to account for the impact of temperatureon viscosity.

The image shows that an initial unsteady period may exist when thetemperature of the fluid in the elongated flow element risessubstantially uniformly. That is, the temperature remains below thevalve operation temperature and, as such, all of the temperatures riseas the temperature of the pipe increases. As shown, at approximately 110seconds, the valve activation temperature is reached and the valvebegins to operate allowing water to flow through the system. As aresult, with incoming water from reservoir being relatively cool,temperatures at the upstream locations in the elongated flow element arereduced and a quasi-steady state of temperatures may be reach. It is tobe appreciated that, as shown, the temperatures at each locationoscillate as the valve opens and closes regularly. Moreover, thequasi-steady state temperatures at each location may drop to aparticular temperature and now that water is flowing, temperatures T₂may benefit from the effect of the heat exchanger and may rise slightlyfrom about 110 seconds to about 150 seconds.

As shown in FIG. 34, a full scale model of the system showed reasonablygood correlation between calculated values of temperature compared toactual measured values.

The above-described model may allow for assessing the impact of changesin the operating parameters. For example, a higher performance heatexchanger (e=0.7) may increase the recovery heat from the treated streamand raise the inlet temperature of the fluid entering the collector. Theresult may be seen in FIG. 35. As shown, the temperatures are moretightly bounded because the temperature at T₂ is higher as a result ofthe increased heat exchanger efficiency and the temperature T₆ remainscontrolled by the valve operation temperature.

The impact of the valve coefficient may be assessed with reference toFIG. 36. There, the valve loss coefficient has been changed from 10 to2. As a result, the temperature levels are mostly unchanged, but thevariation in temperatures at each location has increased.

Another example relating to the impact of the solar loss factor is shownin FIG. 37. The solar loss factor may be impacted by many itemsincluding imperfections in the mirror relating to curvature and surfacereflectivity as well as by the absorptivity of the elongated flowelement. As shown, the solar loss factor has been increased from 0.5 to0.75 with the other parameters remaining the same as those shown in FIG.37. A comparison of FIG. 31 to FIG. 37 demonstrates that while thequasi-steady temperatures are nearly the same, the duration of thetransient heating process may be shortened with higher loss factors.

Given the discussion of pathogen inactivation and the discussion of theperformance calculations of the solar collector, a further analysis canshow results of pathogen inactivation as water flows through the system.For example, Escherichia Coli O3:H6 may be considered. D (i.e., thedecimal reduction time) has been recorded as 401 seconds at temperaturesof 55 degrees C. with a z value of 5.6 degrees C. For these values, andwith Equations 2 and 5, k can be found to be

k=8.66×10⁻¹⁴ ·e ^(0.411T) (l/seconds)  Eq. 17

with temperature expressed in degrees C. Calculations carried out withthe values listed in FIG. 33 may result in a quasi-steady temperaturevariation which begins to occur after approximately 100 seconds ofheating. A conservative approach may be taken to limit the risk ofactive pathogens by applying Equation 6 to the water in the elongatedflow element without giving credit to any heating prior to entry intothe elongated flow element or after it leaves the elongated flowelement. That is, any pathogen inactivation between T₆ and T_(out) maybe ignored.

The result of the calculations are shown in FIG. 38. As shown, pathogeninactivation is displayed as a percentage of initial pathogens. The timeis displayed as a normalized quantity (normalized by the period of thequasi-steady oscillations). That is, time 0 is when the system gets to asteady-state operation. (recall that before that time, the temperatureof the entire elongated flow element reaches the valve operationtemperature so harsher conditions for the pathogen exist during thatperiod). To be clear about what is seen in FIG. 38 as a control volumeof water enters the elongated flow element and flows across theelongated flow element at the temperatures shown in FIG. 31, theinactivation of E. Coli occurs over a two second period.

The calculations which were completed to create the results of FIG. 38may be replicated with other pathogens as well where inactivationkinetic terms are known. Moreover, the methodology described here may beused to calculate results for a wide range of parameter setting.

It is to be appreciated that while the above model has been shown withrespect to a parabolic solar collector other sources of heat may beprovided. That is, for example, where the elongated flow element isexposed to an open flame similar calculations may be performed toestablish pathogen inactivation based on a the amount of heat beingsupplied and its effect on the temperatures in the elongated flowelement.

Examples

In one or more embodiments, a fluid heating system may include a solarcollection system configured for focusing sunlight on a focal axis, anelongated flow element arranged and configured for transporting fluidalong the solar collection system at the focal axis, and a flow-controlassembly comprising thermostatic valves configured to control the flowof the fluid in the elongated flow element such that pathogens presentin the fluid are substantially inactivated before the fluid exits thefluid heating system. The system may also include a preheat heatexchanger configured to utilize fluid exiting the fluid heating systemto heat fluid entering the fluid heating system. The preheat heatexchanger may include a first tortuous pathway and a second tortuouspathway, the first and second tortuous pathways being in substantialalignment with one another such that heat may be exchanged between thepathways. The system may also include a water collecting reservoirconfigured to collect water to be pasteurized. The solar collectionsystem may include a reflective element including a solar film laminatedto a flexible substrate. The solar collection system may also include aframe defining a parabolic shape and the reflective element may be heldin shape by the frame.

In one or more embodiments, the system may include a housing arrangedabout a non-exposed side of the elongated flow element. The housing mayinclude an insulating material. In one or more embodiments, the hood maybe configured to resist convective flow of air by the elongated flowelement. The system may also include a return line, the return linebeing positioned in the housing. The return line may be insulated fromthe elongated flow element. The elongated flow element may be secured tothe control valve assembly at a first end and to the preheat heatexchanger at a second end and the elongated flow element may be securedat each end with an expansion joint.

The system may also include a treated fluid collection tank. The systemmay also include a tracking system configured for directing the solarcollection system at the sun. In one or more embodiments, the collectiontank may include a fluid level sensor in communication with the trackingsystem and the tracking system may be configured to direct the solarcollection system away from the sun when the fluid level sensorindicates that the treated fluid collection tank is full.

The tracking system may include a dual axis tracking system configuredfor directing the solar collection system at the sun. The dual axistracking system may be configured to pivot the solar collection systemabout two axes. The system may also include a support structureincluding an upright support member, an arm portion extending laterallyfrom the upright support member, and a spine portion offset from the armportion and extending substantially parallel to the arm portion. The armportion may be pivotable about a seasonal axis extending perpendicularto the upright support member and perpendicular to the arm portion. Thespine portion may be pivotable about a day axis extending longitudinallyalong the spine portion. The system may also include two actuationassemblies for pivoting the solar collection system about the seasonaland day axes.

In one or more embodiments, a method of operating a fluid heating systemwherein the fluid heating system comprises a parabolic solar collectorand a support structure may be provided. The method may includearranging the fluid heating system along a North/South axis on thesurface of the earth and directing the parabolic solar collector at asun. Directing the parabolic solar collector may include activating acontrol module comprising a GPS communication device, wherein thecontrol module receives GPS data from satellites including coordinatedata defining the location of the fluid heating system on the surface ofa planet, date data, and time data and automatically directs the solarcollector at a sun. Automatically directing the solar collector at thesun may include pivoting the solar collector about a day axis and aseasonal axis. The seasonal axis may be a substantially horizontal axisrelative to the surface of the planet. The day axis may be an axisarranged substantially parallel to a longitudinal length of the solarcollector.

In one or more embodiments, a control valve assembly for passivelycontrolling flow of fluid may include a housing, an inlet, an outlet,and a plurality of thermostatic control valves biased toward a closedposition and arranged within the housing between the inlet and theoutlet. The thermostatic control valves may each be associated withseparate respective flow paths between the inlet and the outlet and havedifferent operating temperatures. The valves may be configured to openat their respective operating temperatures and remain open unless thefluid falls below their respective operating temperature such that whenmultiple thermostatic control valves are open the amount of fluidflowing through the control valve is equal to the addition of the amountof fluid flowing through each valve. The plurality of thermostaticcontrol valves may include three valves. The operating temperatures ofthe thermostatic control valves may be selected to limit the passage ofpathogens through the control valve assembly. The flow rates of thethermostatic control valves may be selected to limit passage ofpathogens through the control valve assembly. The operating temperaturesand the flow rates of the thermostatic control valves may be selected tolimit the passage of pathogens through the control valve assembly.

In one or more embodiments, a first valve of the plurality ofthermostatic control valves may have a range of flow rates and a valveclosing time associated with the amount of time it takes the valve toclose and a portion of a first flow path associated with the first valveextends from the chamber to the first valve and has a length selectedsuch that fluid flowing from the chamber through the portion of thefirst flow path to the valve at the range of flow rates will not reachthe valve in a time less than the closing time.

In one or more embodiments, a method of determining pathogeninactivation may include performing an energy balance on a fluid heatingsystem. Performing an energy balance may include calculatingtemperatures of a fluid at a plurality of locations as the fluid flowsthrough the fluid heating system. The method of determining pathogeninactivation may also include receiving inactivation kinetic dataregarding a pathogen present in the fluid and determining pathogeninactivation amounts based on exposure to the temperatures. Performingan energy balance may include receiving a plurality of input parametersrelating to the fluid heating system. The plurality of input parametersmay relate to a solar collection system and an associated fluid controlsystem. The solar collection system may include a parabolic mirror andthe fluid control system includes an elongated flow element arrangedalong a focal axis of the parabolic mirror. The plurality of locationsmay include locations along the length of the elongated flow element. Inone or more embodiments, the method may include adjusting the inputparameters and calculating revised temperatures at the plurality oflocations. The method may also include determining revised pathogeninactivation amounts based on exposure to the revised temperatures. Themethod may also include receiving inactivation kinetic data regardinganother pathogen present in the fluid. The method may also includedetermining pathogen inactivation amounts of the another pathogen basedon exposure to the temperatures.

In one or more embodiments, a degassing valve may include a cap securedto a housing over a chamber. The cap may include a gas relief orifice.The valve may also include a float arranged in the chamber andconfigured to articulate between an open position and a closed positionwithin the chamber. The float may provide a closing force based on itsbuoyancy when arranged in the closed position. A linkage may be operablyconnected to the cap and the float. The linkage may have a sealingstopper configured to seal the gas relief orifice when the float is in aclosed position. The linkage may further be configured to magnify theclosing force of the float such that a sealing force provided on thesealing stopper by the linkage is a multiple of the float force. Themultiple of the float force may range from approximately 10 toapproximately 30 or from approximately 15 to approximately 25, or fromapproximately 16 to approximately 20. The linkage may include a bottomlinkage bar, a strut, and a top linkage bar. The float may engage thebottom linkage bar at a first end and the bottom linkage bar may bepivotable at a second end about a pivot point having a fixed positionrelative to the cap and the strut may engage the bottom linkage betweenthe first end and the second end. The strut may engage the bottomlinkage bar at a midpoint closer to the second end than the first end.The strut may engage the top linkage bar at a first end and the toplinkage bar may be pivotable at a second end about a pivot point havinga fixed position relative to the cap and the sealing stopper may bepositioned on the top linkage bar between the first end and the secondend. The sealing stopper may be arranged on the top linkage bar at amidpoint closer to the second end than the first end.

In one or more embodiments, a tracking device for tracking the locationof a moving object may include a spine portion for carrying a payload, afirst linear actuation assembly for causing the payload to rotate abouta first axis of rotation, a second linear actuation assembly for causingthe payload to rotate about a second axis of rotation, and a controlmodule configured to determine a position of a moving object in the sky.The control module may be further configured to operate the first andsecond linear actuation assemblies to direct the payload relative to themoving object. In one or more embodiments, the first linear actuationassembly and second linear actuation assembly may each include a linearactuator and a motor. In one or more embodiments, the first linearactuation assembly and second linear actuation assembly may include alinear absolute encoder. In one embodiment, the second axis of rotationmay align with a longitudinal axis of the spine portion and the firstaxis of rotation may be orthogonal to the second axis of rotation. Inone or more embodiments, the tracking device may also include an uprightportion supporting the spine portion, an arm portion between the spineportion and the upright portion, and a single axis support coupling thearm portion to the upright portion. The first actuation assembly may becoupled to the upright portion and pivotably coupled to the arm portion.The second actuation assembly may be coupled to the arm portion andpivotably coupled to the spine portion with a torque arm. The spineportion may remain static with respect to a third axis of rotationdefined as a vertical axis aligned with the upright portion. The devicemay also be configured for wireless communication.

In one or more other embodiments, a solar tracking device for trackingthe location of the sun over a period of time may include a spineportion carrying at least one of a solar panel, solar concentrator, andheliostat, a first linear actuation assembly for causing the one or moresolar panels to rotate about a first axis of rotation, a second linearactuation assembly for causing the one or more solar panels to rotateabout a second axis of rotation, and a control module configured toreceive Global Positioning System data comprising the tracking device'slocation, the time, and the date, determine the location of the sunbased on the Global Positioning System data, direct the first and secondactuation assemblies to position the one or more solar panels such thatthe one or more solar panels are directed relative to the sun. The firstlinear actuation assembly and second linear actuation assembly mayinclude a linear actuator and a motor. The first linear actuationassembly and second linear actuation assembly may each further include alinear absolute encoder. The second axis of rotation may align with alongitudinal axis of the spine portion the first axis of rotation may beorthogonal to the second axis of rotation. The tracking device may alsoinclude an upright portion supporting the spine portion, an arm portionbetween the spine portion and the upright portion, and a single axissupport coupling the arm portion to the upright portion. The firstactuation assembly may be coupled to the upright portion and pivotablycoupled to the arm portion. The second actuation assembly may be coupledto the arm portion and pivotably coupled to the spine portion with atorque arm. The spine portion may include a first end and a second endand the first end may be directed North and the second end may bedirected South. The device may be configured for wireless communication.The first and second actuation assemblies may include referencing anerror correction lookup table.

In one or more embodiments, a method for directing a payload relative toa moving object may include receiving Global Positioning System datarelated to the time, date, and location of a tracking device,determining an azimuth and altitude of the moving object with respect tothe tracking device, calculating a first angular motion pathcorresponding to a first axis of rotation of the payload and a secondangular motion path corresponding to a second axis of rotation of thepayload, calculating a first linear motion path and a second linearmotion path from the first and second angular motion paths, anddirecting the device to rotate the payload in accordance with the firstand second linear motion paths. The method may also include repeatingthe method at timed intervals over the course of a day. The method mayalso include calculating an error correction for the first linear motionpath and second linear motion path. The error correction may bedetermined by referencing an error correction lookup table and usingbicubic interpolation to interpolate an error correction.

In one or more embodiments, a tower structure may include a trackingdevice for tracking the location of a moving object. The tracking devicemay include a spine portion for carrying a payload, a first linearactuation assembly causing the payload to rotate about a first axis ofrotation, a second linear actuation assembly causing the payload torotate about a second axis of rotation, and a control module configuredto determine a position of a moving object in the sky, the controlmodule further configured to operate the first and second linearactuation assemblies to direct the payload relative to the movingobject. The tower structure may include a communication tower. The towerstructure may include a solar power tower. The payload may include aheliostat.

For purposes of this disclosure, any system described herein may includeany instrumentality or aggregate of instrumentalities operable tocompute, calculate, determine, classify, process, transmit, receive,retrieve, originate, switch, store, display, communicate, manifest,detect, record, reproduce, handle, or utilize any form of information,intelligence, or data for business, scientific, control, or otherpurposes. For example, a system or any portion thereof may be a personalcomputer (e.g., desktop or laptop), tablet computer, mobile device(e.g., personal digital assistant (PDA) or smart phone), server (e.g.,blade server or rack server), a network storage device, or any othersuitable device or combination of devices and may vary in size, shape,performance, functionality, and price. A system may include randomaccess memory (RAM), one or more processing resources such as a centralprocessing unit (CPU) or hardware or software control logic, ROM, and/orother types of nonvolatile memory. Additional components of a system mayinclude one or more disk drives or one or more mass storage devices, oneor more network ports for communicating with external devices as well asvarious input and output (I/O) devices, such as a keyboard, a mouse,touchscreen and/or a video display. Mass storage devices may include,but are not limited to, a hard disk drive, floppy disk drive, CD-ROMdrive, smart drive, flash drive, or other types of non-volatile datastorage, a plurality of storage devices, or any combination of storagedevices. A system may include what is referred to as a user interface,which may generally include a display, mouse or other cursor controldevice, keyboard, button, touchpad, touch screen, microphone, camera,video recorder, speaker, LED, light, joystick, switch, buzzer, bell,and/or other user input/output device for communicating with one or moreusers or for entering information into the system. Output devices mayinclude any type of device for presenting information to a user,including but not limited to, a computer monitor, flat-screen display,or other visual display, a printer, and/or speakers or any other devicefor providing information in audio form, such as a telephone, aplurality of output devices, or any combination of output devices. Asystem may also include one or more buses operable to transmitcommunications between the various hardware components.

One or more programs or applications, such as a web browser, and/orother applications may be stored in one or more of the system datastorage devices. Programs or applications may be loaded in part or inwhole into a main memory or processor during execution by the processor.One or more processors may execute applications or programs to runsystems or methods of the present disclosure, or portions thereof,stored as executable programs or program code in the memory, or receivedfrom the Internet or other network. Any commercial or freeware webbrowser or other application capable of retrieving content from anetwork and displaying pages or screens may be used. In someembodiments, a customized application may be used to access, display,and update information.

Hardware and software components of the present disclosure, as discussedherein, may be integral portions of a single computer or server or maybe connected parts of a computer network. The hardware and softwarecomponents may be located within a single location or, in otherembodiments, portions of the hardware and software components may bedivided among a plurality of locations and connected directly or througha global computer information network, such as the Internet.

As will be appreciated by one of skill in the art, the variousembodiments of the present disclosure may be embodied as a method(including, for example, a computer-implemented process, a businessprocess, and/or any other process), apparatus (including, for example, asystem, machine, device, computer program product, and/or the like), ora combination of the foregoing. Accordingly, embodiments of the presentdisclosure may take the form of an entirely hardware embodiment, anentirely software embodiment (including firmware, middleware, microcode,hardware description languages, etc.), or an embodiment combiningsoftware and hardware aspects. Furthermore, embodiments of the presentdisclosure may take the form of a computer program product on acomputer-readable medium or computer-readable storage medium, havingcomputer-executable program code embodied in the medium, that defineprocesses or methods described herein. A processor or processors mayperform the necessary tasks defined by the computer-executable programcode. Computer-executable program code for carrying out operations ofembodiments of the present disclosure may be written in an objectoriented, scripted or unscripted programming language such as Java,Perl, PHP, Visual Basic, Smalltalk, C++, or the like. However, thecomputer program code for carrying out operations of embodiments of thepresent disclosure may also be written in conventional proceduralprogramming languages, such as the C programming language or similarprogramming languages. A code segment may represent a procedure, afunction, a subprogram, a program, a routine, a subroutine, a module, anobject, a software package, a class, or any combination of instructions,data structures, or program statements. A code segment may be coupled toanother code segment or a hardware circuit by passing and/or receivinginformation, data, arguments, parameters, or memory contents.Information, arguments, parameters, data, etc. may be passed, forwarded,or transmitted via any suitable means including memory sharing, messagepassing, token passing, network transmission, etc.

In the context of this document, a computer readable medium may be anymedium that can contain, store, communicate, or transport the programfor use by or in connection with the systems disclosed herein. Thecomputer-executable program code may be transmitted using anyappropriate medium, including but not limited to the Internet, opticalfiber cable, radio frequency (RF) signals or other wireless signals, orother mediums. The computer readable medium may be, for example but isnot limited to, an electronic, magnetic, optical, electromagnetic,infrared, or semiconductor system, apparatus, or device. More specificexamples of suitable computer readable medium include, but are notlimited to, an electrical connection having one or more wires or atangible storage medium such as a portable computer diskette, a harddisk, a random access memory (RAM), a read-only memory (ROM), anerasable programmable read-only memory (EPROM or Flash memory), acompact disc read-only memory (CD-ROM), or other optical or magneticstorage device. Computer-readable media includes, but is not to beconfused with, computer-readable storage medium, which is intended tocover all physical, non-transitory, or similar embodiments ofcomputer-readable media.

Various embodiments of the present disclosure may be described hereinwith reference to flowchart illustrations and/or block diagrams ofmethods, apparatus (systems), and computer program products. It isunderstood that each block of the flowchart illustrations and/or blockdiagrams, and/or combinations of blocks in the flowchart illustrationsand/or block diagrams, can be implemented by computer-executable programcode portions. These computer-executable program code portions may beprovided to a processor of a general purpose computer, special purposecomputer, or other programmable data processing apparatus to produce aparticular machine, such that the code portions, which execute via theprocessor of the computer or other programmable data processingapparatus, create mechanisms for implementing the functions/actsspecified in the flowchart and/or block diagram block or blocks.Alternatively, computer program implemented steps or acts may becombined with operator or human implemented steps or acts in order tocarry out an embodiment of the invention.

Additionally, although a flowchart may illustrate a method as asequential process, many of the operations in the flowcharts illustratedherein can be performed in parallel or concurrently. In addition, theorder of the method steps illustrated in a flowchart may be rearrangedfor some embodiments. Similarly, a method illustrated in a flow chartcould have additional steps not included therein or fewer steps thanthose shown. A method step may correspond to a method, a function, aprocedure, a subroutine, a subprogram, etc.

As used herein, the terms “substantially” or “generally” refer to thecomplete or nearly complete extent or degree of an action,characteristic, property, state, structure, item, or result. Forexample, an object that is “substantially” or “generally” enclosed wouldmean that the object is either completely enclosed or nearly completelyenclosed. The exact allowable degree of deviation from absolutecompleteness may in some cases depend on the specific context. However,generally speaking, the nearness of completion will be so as to havegenerally the same overall result as if absolute and total completionwere obtained. The use of “substantially” or “generally” is equallyapplicable when used in a negative connotation to refer to the completeor near complete lack of an action, characteristic, property, state,structure, item, or result. For example, an element, combination,embodiment, or composition that is “substantially free of” or “generallyfree of” an ingredient or element may still actually contain such itemas long as there is generally no measurable effect thereof.

In the foregoing description various embodiments of the presentdisclosure have been presented for the purpose of illustration anddescription. They are not intended to be exhaustive or to limit theinvention to the precise form disclosed. Obvious modifications orvariations are possible in light of the above teachings. The variousembodiments were chosen and described to provide the best illustrationof the principals of the disclosure and their practical application, andto enable one of ordinary skill in the art to utilize the variousembodiments with various modifications as are suited to the particularuse contemplated. All such modifications and variations are within thescope of the present disclosure as determined by the appended claimswhen interpreted in accordance with the breadth they are fairly,legally, and equitably entitled.

What is claimed is:
 1. A control valve assembly for passivelycontrolling flow of fluid, comprising: a housing; an inlet; an outlet;and a plurality of thermostatic control valves biased toward a closedposition and arranged within the housing between the inlet and theoutlet, the thermostatic control valves each being associated withseparate respective flow paths between the inlet and the outlet andhaving different operating temperatures, wherein the valves areconfigured to open at their respective operating temperatures and remainopen unless the fluid falls below their respective operating temperaturesuch that when multiple thermostatic control valves are open the amountof fluid flowing through the control valve is equal to the addition ofthe amount of fluid flowing through each valve.
 2. The control valveassembly of claim 2, wherein the plurality of thermostatic controlvalves comprises three valves.
 3. The control valve assembly of claim 1,wherein the operating temperatures of the thermostatic control valvesare selected to limit the passage of pathogens through the control valveassembly.
 4. The control valve assembly of claim 1, wherein the flowrates of the thermostatic control valves are selected to limit passageof pathogens through the control valve assembly.
 5. The control valveassembly of claim 1, wherein both the operating temperatures and theflow rates of the thermostatic control valves are selected to limit thepassage of pathogens through the control valve assembly.
 6. The controlvalve assembly of claim 1, wherein a first valve of the plurality ofthermostatic control valves has a range of flow rates and a valveclosing time associated with the amount of time it takes the valve toclose and a portion of a first flow path associated with the first valveextends from the chamber to the first valve and has a length selectedsuch that fluid flowing from the chamber through the portion of thefirst flow path to the valve at the range of flow rates will not reachthe valve in a time less than the closing time.
 7. A degassing valve,comprising: a cap secured to a housing over a chamber and having a gasrelief orifice; a float arranged in the chamber and configured toarticulate between an open position and a closed position within thechamber, the float providing a closing force based on its buoyancy whenarranged in the closed position; a linkage operably connected to the capand the float, the linkage having a sealing stopper configured to sealthe gas relief orifice when the float is in a closed position, thelinkage further configured to magnify the closing force of the floatsuch that a sealing force provided on the sealing stopper by the linkageis a multiple of the float force.
 8. The degassing valve of claim 7,wherein the multiple of the float force ranges from approximately 10 toapproximately
 30. 9. The degassing valve of claim 8, wherein themultiple of the float force ranges from approximately 15 toapproximately
 25. 10. The degassing valve of claim 9, wherein themultiple of the float force ranges from approximately 16 toapproximately
 20. 11. The degassing valve of claim 1, wherein thelinkage includes a bottom linkage bar, a strut, and a top linkage bar.12. The degassing valve of claim 11, wherein the float engages thebottom linkage bar at a first end and the bottom linkage bar ispivotable at a second end about a pivot point having a fixed positionrelative to the cap and the strut engages the bottom linkage between thefirst end and the second end.
 13. The degassing valve of claim 12,wherein the strut engages the bottom linkage bar at a midpoint closer tothe second end than the first end.
 14. The degassing valve of claim 13,wherein the strut engages the top linkage bar at a first end and the toplinkage bar is pivotable at a second end about a pivot point having afixed position relative to the cap and the sealing stopper is positionedon the top linkage bar between the first end and the second end.
 15. Thedegassing valve of claim 14, wherein the sealing stopper is arranged onthe top linkage bar at a midpoint closer to the second end than thefirst end.